feat: add alt text support for images with accessibility

app/src/main/java/com/swoosh/microblog/data/MobiledocBuilder.kt

@@ -17,18 +17,43 @@ object MobiledocBuilder {
         linkUrl: String?,
         linkTitle: String?,
         linkDescription: String?
+    ): String {
+        return build(text, linkUrl, linkTitle, linkDescription, null, null)
+    }
+
+    fun build(
+        text: String,
+        linkUrl: String?,
+        linkTitle: String?,
+        linkDescription: String?,
+        imageUrl: String?,
+        imageAlt: String?
     ): String {
         val escapedText = escapeForJson(text).replace("\n", "\\n")
 
-        val cards = if (linkUrl != null) {
+        val cardsList = mutableListOf<String>()
+        val cardSections = mutableListOf<String>()
+
+        // Image card
+        if (imageUrl != null) {
+            val escapedImgUrl = escapeForJson(imageUrl)
+            val escapedAlt = imageAlt?.let { escapeForJson(it) } ?: ""
+            cardSections.add("[10,${cardsList.size}]")
+            cardsList.add("""["image",{"src":"$escapedImgUrl","alt":"$escapedAlt","caption":""}]""")
+        }
+
+        // Bookmark card
+        if (linkUrl != null) {
             val escapedUrl = escapeForJson(linkUrl)
             val escapedTitle = linkTitle?.let { escapeForJson(it) } ?: ""
             val escapedDesc = linkDescription?.let { escapeForJson(it) } ?: ""
-            """["bookmark",{"url":"$escapedUrl","metadata":{"title":"$escapedTitle","description":"$escapedDesc"}}]"""
+            cardSections.add("[10,${cardsList.size}]")
-        } else ""
+            cardsList.add("""["bookmark",{"url":"$escapedUrl","metadata":{"title":"$escapedTitle","description":"$escapedDesc"}}]""")
+        }
 
-        val cardSection = if (linkUrl != null) ",[10,0]" else ""
+        val cards = cardsList.joinToString(",")
-        return """{"version":"0.3.1","atoms":[],"cards":[$cards],"markups":[],"sections":[[1,"p",[[0,[],0,"$escapedText"]]]$cardSection]}"""
+        val extraSections = if (cardSections.isNotEmpty()) "," + cardSections.joinToString(",") else ""
+        return """{"version":"0.3.1","atoms":[],"cards":[$cards],"markups":[],"sections":[[1,"p",[[0,[],0,"$escapedText"]]]$extraSections]}"""
     }
 
     internal fun escapeForJson(value: String): String {

app/src/main/java/com/swoosh/microblog/data/db/AppDatabase.kt

@@ -5,9 +5,11 @@ import androidx.room.Database
 import androidx.room.Room
 import androidx.room.RoomDatabase
 import androidx.room.TypeConverters
+import androidx.room.migration.Migration
+import androidx.sqlite.db.SupportSQLiteDatabase
 import com.swoosh.microblog.data.model.LocalPost
 
-@Database(entities = [LocalPost::class], version = 1, exportSchema = false)
+@Database(entities = [LocalPost::class], version = 2, exportSchema = false)
 @TypeConverters(Converters::class)
 abstract class AppDatabase : RoomDatabase() {
 
@@ -17,13 +19,21 @@ abstract class AppDatabase : RoomDatabase() {
         @Volatile
         private var INSTANCE: AppDatabase? = null
 
+        val MIGRATION_1_2 = object : Migration(1, 2) {
+            override fun migrate(db: SupportSQLiteDatabase) {
+                db.execSQL("ALTER TABLE local_posts ADD COLUMN imageAlt TEXT DEFAULT NULL")
+            }
+        }
+
         fun getInstance(context: Context): AppDatabase {
             return INSTANCE ?: synchronized(this) {
                 val instance = Room.databaseBuilder(
                     context.applicationContext,
                     AppDatabase::class.java,
                     "swoosh_database"
-                ).build()
+                )
+                    .addMigrations(MIGRATION_1_2)
+                    .build()
                 INSTANCE = instance
                 instance
             }

app/src/main/java/com/swoosh/microblog/data/model/GhostModels.kt

@@ -36,6 +36,7 @@ data class GhostPost(
     val mobiledoc: String? = null,
     val status: String? = null,
     val feature_image: String? = null,
+    val feature_image_alt: String? = null,
     val created_at: String? = null,
     val updated_at: String? = null,
     val published_at: String? = null,
@@ -66,6 +67,7 @@ data class LocalPost(
     val linkTitle: String? = null,
     val linkDescription: String? = null,
     val linkImageUrl: String? = null,
+    val imageAlt: String? = null,
     val scheduledAt: String? = null,
     val createdAt: Long = System.currentTimeMillis(),
     val updatedAt: Long = System.currentTimeMillis(),
@@ -95,6 +97,7 @@ data class FeedPost(
     val textContent: String,
     val htmlContent: String?,
     val imageUrl: String?,
+    val imageAlt: String? = null,
     val linkUrl: String?,
     val linkTitle: String?,
     val linkDescription: String?,

app/src/main/java/com/swoosh/microblog/ui/composer/ComposerScreen.kt

@@ -3,8 +3,10 @@ package com.swoosh.microblog.ui.composer
 import android.net.Uri
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -18,7 +20,11 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import coil.compose.AsyncImage
@@ -37,6 +43,7 @@ fun ComposerScreen(
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     var showLinkDialog by remember { mutableStateOf(false) }
     var showDatePicker by remember { mutableStateOf(false) }
+    var showAltTextDialog by remember { mutableStateOf(false) }
     var linkInput by remember { mutableStateOf("") }
 
     // Load post for editing
@@ -120,11 +127,14 @@ fun ComposerScreen(
                 Box {
                     AsyncImage(
                         model = state.imageUri,
-                        contentDescription = "Selected image",
+                        contentDescription = state.imageAlt.ifBlank { "Selected image" },
                         modifier = Modifier
                             .fillMaxWidth()
                             .height(200.dp)
-                            .clip(MaterialTheme.shapes.medium),
+                            .clip(MaterialTheme.shapes.medium)
+                            .semantics {
+                                contentDescription = state.imageAlt.ifBlank { "Selected image" }
+                            },
                         contentScale = ContentScale.Crop
                     )
                     IconButton(
@@ -136,6 +146,36 @@ fun ComposerScreen(
                             tint = MaterialTheme.colorScheme.onSurface
                         )
                     }
+                    // ALT badge when alt text is set
+                    if (state.imageAlt.isNotBlank()) {
+                        Text(
+                            text = "ALT",
+                            modifier = Modifier
+                                .align(Alignment.BottomStart)
+                                .padding(8.dp)
+                                .background(
+                                    MaterialTheme.colorScheme.inverseSurface.copy(alpha = 0.8f),
+                                    RoundedCornerShape(4.dp)
+                                )
+                                .padding(horizontal = 6.dp, vertical = 2.dp),
+                            color = MaterialTheme.colorScheme.inverseOnSurface,
+                            fontSize = 11.sp,
+                            fontWeight = FontWeight.Bold
+                        )
+                    }
+                }
+
+                // Add alt text button
+                Spacer(modifier = Modifier.height(4.dp))
+                TextButton(
+                    onClick = { showAltTextDialog = true },
+                    contentPadding = PaddingValues(horizontal = 0.dp)
+                ) {
+                    Text(
+                        text = if (state.imageAlt.isBlank()) "Add alt text" else "Edit alt text",
+                        style = MaterialTheme.typography.labelMedium,
+                        color = MaterialTheme.colorScheme.primary
+                    )
                 }
             }
 
@@ -302,6 +342,49 @@ fun ComposerScreen(
             onDismiss = { showDatePicker = false }
         )
     }
+
+    // Alt text dialog
+    if (showAltTextDialog) {
+        var altInput by remember { mutableStateOf(state.imageAlt) }
+        AlertDialog(
+            onDismissRequest = { showAltTextDialog = false },
+            title = { Text("Alt Text") },
+            text = {
+                Column {
+                    OutlinedTextField(
+                        value = altInput,
+                        onValueChange = { altInput = it.take(250) },
+                        placeholder = { Text("Describe this image for people who can't see it") },
+                        modifier = Modifier.fillMaxWidth(),
+                        minLines = 2,
+                        maxLines = 4,
+                        supportingText = {
+                            Text(
+                                "${altInput.length}/250",
+                                style = MaterialTheme.typography.labelSmall,
+                                color = if (altInput.length >= 250)
+                                    MaterialTheme.colorScheme.error
+                                else MaterialTheme.colorScheme.onSurfaceVariant
+                            )
+                        }
+                    )
+                }
+            },
+            confirmButton = {
+                TextButton(onClick = {
+                    viewModel.updateImageAlt(altInput)
+                    showAltTextDialog = false
+                }) {
+                    Text("Save")
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { showAltTextDialog = false }) {
+                    Text("Cancel")
+                }
+            }
+        )
+    }
 }
 
 @OptIn(ExperimentalMaterial3Api::class)

app/src/main/java/com/swoosh/microblog/ui/composer/ComposerViewModel.kt

@@ -35,6 +35,7 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
             it.copy(
                 text = post.textContent,
                 imageUri = post.imageUrl?.let { url -> Uri.parse(url) },
+                imageAlt = post.imageAlt ?: "",
                 linkPreview = if (post.linkUrl != null) LinkPreview(
                     url = post.linkUrl,
                     title = post.linkTitle,
@@ -51,7 +52,17 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
     }
 
     fun setImage(uri: Uri?) {
-        _uiState.update { it.copy(imageUri = uri) }
+        _uiState.update {
+            if (uri == null) {
+                it.copy(imageUri = null, imageAlt = "")
+            } else {
+                it.copy(imageUri = uri)
+            }
+        }
+    }
+
+    fun updateImageAlt(alt: String) {
+        _uiState.update { it.copy(imageAlt = alt.take(250)) }
     }
 
     fun fetchLinkPreview(url: String) {
@@ -89,6 +100,8 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
 
             val title = state.text.take(60)
 
+            val altText = state.imageAlt.ifBlank { null }
+
             if (status == PostStatus.DRAFT || !repository.isNetworkAvailable()) {
                 // Save locally
                 val localPost = LocalPost(
@@ -98,6 +111,7 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
                     content = state.text,
                     status = status,
                     imageUri = state.imageUri?.toString(),
+                    imageAlt = altText,
                     linkUrl = state.linkPreview?.url,
                     linkTitle = state.linkPreview?.title,
                     linkDescription = state.linkPreview?.description,
@@ -127,13 +141,21 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
                 )
             }
 
-            val mobiledoc = MobiledocBuilder.build(state.text, state.linkPreview)
+            val mobiledoc = MobiledocBuilder.build(
+                state.text,
+                state.linkPreview?.url,
+                state.linkPreview?.title,
+                state.linkPreview?.description,
+                featureImage,
+                altText
+            )
 
             val ghostPost = GhostPost(
                 title = title,
                 mobiledoc = mobiledoc,
                 status = status.name.lowercase(),
                 feature_image = featureImage,
+                feature_image_alt = altText,
                 published_at = state.scheduledAt,
                 visibility = "public"
             )
@@ -159,6 +181,7 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
                         status = status,
                         imageUri = state.imageUri?.toString(),
                         uploadedImageUrl = featureImage,
+                        imageAlt = altText,
                         linkUrl = state.linkPreview?.url,
                         linkTitle = state.linkPreview?.title,
                         linkDescription = state.linkPreview?.description,
@@ -185,6 +208,7 @@ class ComposerViewModel(application: Application) : AndroidViewModel(application
 data class ComposerUiState(
     val text: String = "",
     val imageUri: Uri? = null,
+    val imageAlt: String = "",
     val linkPreview: LinkPreview? = null,
     val isLoadingLink: Boolean = false,
     val scheduledAt: String? = null,

app/src/main/java/com/swoosh/microblog/ui/detail/DetailScreen.kt

@@ -12,6 +12,9 @@ import androidx.compose.runtime.*
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.unit.dp
 import coil.compose.AsyncImage
 import com.swoosh.microblog.data.model.FeedPost
@@ -81,12 +84,26 @@ fun DetailScreen(
                 Spacer(modifier = Modifier.height(16.dp))
                 AsyncImage(
                     model = post.imageUrl,
-                    contentDescription = "Post image",
+                    contentDescription = post.imageAlt ?: "Post image",
                     modifier = Modifier
                         .fillMaxWidth()
-                        .clip(MaterialTheme.shapes.medium),
+                        .clip(MaterialTheme.shapes.medium)
+                        .semantics {
+                            contentDescription = post.imageAlt ?: "Post image"
+                        },
                     contentScale = ContentScale.FillWidth
                 )
+                // Alt text display
+                if (!post.imageAlt.isNullOrBlank()) {
+                    Spacer(modifier = Modifier.height(6.dp))
+                    Text(
+                        text = "Alt: ${post.imageAlt}",
+                        style = MaterialTheme.typography.bodySmall.copy(
+                            fontStyle = FontStyle.Italic
+                        ),
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                }
             }
 
             // Link preview

app/src/main/java/com/swoosh/microblog/ui/feed/FeedScreen.kt

@@ -1,10 +1,12 @@
 package com.swoosh.microblog.ui.feed
 
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.ExperimentalMaterialApi
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
@@ -20,9 +22,13 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import coil.compose.AsyncImage
@@ -251,15 +257,56 @@ fun PostCard(
             // Image thumbnail
             if (post.imageUrl != null) {
                 Spacer(modifier = Modifier.height(8.dp))
+                var showAltPopup by remember { mutableStateOf(false) }
+                Box {
                     AsyncImage(
                         model = post.imageUrl,
-                    contentDescription = "Post image",
+                        contentDescription = post.imageAlt ?: "Post image",
                         modifier = Modifier
                             .fillMaxWidth()
                             .height(180.dp)
-                        .clip(MaterialTheme.shapes.medium),
+                            .clip(MaterialTheme.shapes.medium)
+                            .semantics {
+                                contentDescription = post.imageAlt ?: "Post image"
+                            },
                         contentScale = ContentScale.Crop
                     )
+                    if (!post.imageAlt.isNullOrBlank()) {
+                        Text(
+                            text = "ALT",
+                            modifier = Modifier
+                                .align(Alignment.BottomStart)
+                                .padding(8.dp)
+                                .clip(RoundedCornerShape(4.dp))
+                                .background(
+                                    MaterialTheme.colorScheme.inverseSurface.copy(alpha = 0.8f)
+                                )
+                                .clickable { showAltPopup = !showAltPopup }
+                                .padding(horizontal = 6.dp, vertical = 2.dp),
+                            color = MaterialTheme.colorScheme.inverseOnSurface,
+                            fontSize = 11.sp,
+                            fontWeight = FontWeight.Bold
+                        )
+                    }
+                }
+                // Alt text popup
+                if (showAltPopup && !post.imageAlt.isNullOrBlank()) {
+                    Card(
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .padding(top = 4.dp),
+                        colors = CardDefaults.cardColors(
+                            containerColor = MaterialTheme.colorScheme.surfaceVariant
+                        )
+                    ) {
+                        Text(
+                            text = post.imageAlt,
+                            modifier = Modifier.padding(8.dp),
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                    }
+                }
             }
 
             // Link preview

app/src/main/java/com/swoosh/microblog/ui/feed/FeedViewModel.kt

@@ -144,6 +144,7 @@ class FeedViewModel(application: Application) : AndroidViewModel(application) {
         textContent = plaintext ?: html?.replace(Regex("<[^>]*>"), "") ?: "",
         htmlContent = html,
         imageUrl = feature_image,
+        imageAlt = feature_image_alt,
         linkUrl = null,
         linkTitle = null,
         linkDescription = null,
@@ -162,6 +163,7 @@ class FeedViewModel(application: Application) : AndroidViewModel(application) {
         textContent = content,
         htmlContent = htmlContent,
         imageUrl = uploadedImageUrl ?: imageUri,
+        imageAlt = imageAlt,
         linkUrl = linkUrl,
         linkTitle = linkTitle,
         linkDescription = linkDescription,

app/src/main/java/com/swoosh/microblog/worker/PostUploadWorker.kt

@@ -37,7 +37,10 @@ class PostUploadWorker(
                 featureImage = imageResult.getOrNull()
             }
 
-            val mobiledoc = MobiledocBuilder.build(post.content, post.linkUrl, post.linkTitle, post.linkDescription)
+            val mobiledoc = MobiledocBuilder.build(
+                post.content, post.linkUrl, post.linkTitle, post.linkDescription,
+                featureImage, post.imageAlt
+            )
 
             val ghostPost = GhostPost(
                 title = post.title,
@@ -48,6 +51,7 @@ class PostUploadWorker(
                     else -> "draft"
                 },
                 feature_image = featureImage,
+                feature_image_alt = post.imageAlt,
                 published_at = post.scheduledAt,
                 visibility = "public"
             )

app/src/test/java/com/swoosh/microblog/data/MobiledocBuilderTest.kt

@@ -251,4 +251,161 @@ class MobiledocBuilderTest {
     fun `escapeForJson handles empty string`() {
         assertEquals("", MobiledocBuilder.escapeForJson(""))
     }
+
+    // --- Image card with alt text ---
+
+    @Test
+    fun `build with image card produces valid JSON`() {
+        val result = MobiledocBuilder.build(
+            "Post text", null, null, null,
+            "https://example.com/photo.jpg", "A sunset"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull(json)
+    }
+
+    @Test
+    fun `build with image card includes image type`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "Alt text"
+        )
+        assertTrue("Should contain image card type", result.contains("\"image\""))
+    }
+
+    @Test
+    fun `build with image card includes src`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "Alt text"
+        )
+        assertTrue("Should contain image src", result.contains("https://example.com/photo.jpg"))
+    }
+
+    @Test
+    fun `build with image card includes alt text`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "A beautiful sunset"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val cards = json.getAsJsonArray("cards")
+        assertEquals(1, cards.size())
+        val card = cards.get(0).asJsonArray
+        assertEquals("image", card.get(0).asString)
+        val cardData = card.get(1).asJsonObject
+        assertEquals("A beautiful sunset", cardData.get("alt").asString)
+    }
+
+    @Test
+    fun `build with image card and null alt uses empty string`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", null
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val cards = json.getAsJsonArray("cards")
+        val card = cards.get(0).asJsonArray
+        val cardData = card.get(1).asJsonObject
+        assertEquals("", cardData.get("alt").asString)
+    }
+
+    @Test
+    fun `build with image card includes caption field`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "Alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val card = json.getAsJsonArray("cards").get(0).asJsonArray
+        val cardData = card.get(1).asJsonObject
+        assertEquals("", cardData.get("caption").asString)
+    }
+
+    @Test
+    fun `build with image card has card section`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "Alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        assertEquals("Should have text section and image card section", 2, sections.size())
+    }
+
+    @Test
+    fun `build with image and link has both cards`() {
+        val result = MobiledocBuilder.build(
+            "Text", "https://link.com", "Link Title", "Link Desc",
+            "https://example.com/photo.jpg", "Image alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val cards = json.getAsJsonArray("cards")
+        assertEquals("Should have image card and bookmark card", 2, cards.size())
+        // Image card comes first
+        assertEquals("image", cards.get(0).asJsonArray.get(0).asString)
+        assertEquals("bookmark", cards.get(1).asJsonArray.get(0).asString)
+    }
+
+    @Test
+    fun `build with image and link has three sections`() {
+        val result = MobiledocBuilder.build(
+            "Text", "https://link.com", "Title", "Desc",
+            "https://example.com/photo.jpg", "Alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        assertEquals("Should have text, image card, and bookmark card sections", 3, sections.size())
+    }
+
+    @Test
+    fun `build with image card escapes alt text`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "He said \"hello\""
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull("Should produce valid JSON with escaped alt text", json)
+    }
+
+    @Test
+    fun `build without image produces no image card`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            null, null
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertTrue("Should have no cards", json.getAsJsonArray("cards").isEmpty)
+    }
+
+    @Test
+    fun `build with image card section references correct card index`() {
+        val result = MobiledocBuilder.build(
+            "Text", null, null, null,
+            "https://example.com/photo.jpg", "Alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        val cardSection = sections.get(1).asJsonArray
+        assertEquals(10, cardSection.get(0).asInt)
+        assertEquals(0, cardSection.get(1).asInt)
+    }
+
+    @Test
+    fun `build with image and link card sections reference correct indices`() {
+        val result = MobiledocBuilder.build(
+            "Text", "https://link.com", "Title", null,
+            "https://example.com/photo.jpg", "Alt"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        // Image card section at index 0
+        val imgSection = sections.get(1).asJsonArray
+        assertEquals(10, imgSection.get(0).asInt)
+        assertEquals(0, imgSection.get(1).asInt)
+        // Bookmark card section at index 1
+        val bookmarkSection = sections.get(2).asJsonArray
+        assertEquals(10, bookmarkSection.get(0).asInt)
+        assertEquals(1, bookmarkSection.get(1).asInt)
+    }
 }

app/src/test/java/com/swoosh/microblog/data/model/GhostModelsTest.kt

@@ -72,6 +72,7 @@ class GhostModelsTest {
         assertNull(post.mobiledoc)
         assertNull(post.status)
         assertNull(post.feature_image)
+        assertNull(post.feature_image_alt)
         assertNull(post.created_at)
         assertNull(post.updated_at)
         assertNull(post.published_at)
@@ -252,4 +253,108 @@ class GhostModelsTest {
         assertNull(preview.description)
         assertNull(preview.imageUrl)
     }
+
+    // --- Alt text ---
+
+    @Test
+    fun `LocalPost default imageAlt is null`() {
+        val post = LocalPost()
+        assertNull(post.imageAlt)
+    }
+
+    @Test
+    fun `LocalPost stores imageAlt`() {
+        val post = LocalPost(imageAlt = "A sunset over the ocean")
+        assertEquals("A sunset over the ocean", post.imageAlt)
+    }
+
+    @Test
+    fun `GhostPost default feature_image_alt is null`() {
+        val post = GhostPost()
+        assertNull(post.feature_image_alt)
+    }
+
+    @Test
+    fun `GhostPost stores feature_image_alt`() {
+        val post = GhostPost(
+            feature_image = "https://example.com/img.jpg",
+            feature_image_alt = "A beautiful landscape"
+        )
+        assertEquals("A beautiful landscape", post.feature_image_alt)
+    }
+
+    @Test
+    fun `GhostPost serializes feature_image_alt to JSON`() {
+        val post = GhostPost(
+            title = "Test",
+            feature_image = "https://example.com/img.jpg",
+            feature_image_alt = "Alt description"
+        )
+        val json = gson.toJson(post)
+        assertTrue(json.contains("\"feature_image_alt\":\"Alt description\""))
+    }
+
+    @Test
+    fun `GhostPost deserializes feature_image_alt from JSON`() {
+        val json = """{"id":"1","feature_image":"https://example.com/img.jpg","feature_image_alt":"Test alt"}"""
+        val post = gson.fromJson(json, GhostPost::class.java)
+        assertEquals("Test alt", post.feature_image_alt)
+    }
+
+    @Test
+    fun `GhostPost deserializes with missing feature_image_alt`() {
+        val json = """{"id":"1","feature_image":"https://example.com/img.jpg"}"""
+        val post = gson.fromJson(json, GhostPost::class.java)
+        assertNull(post.feature_image_alt)
+    }
+
+    @Test
+    fun `FeedPost default imageAlt is null`() {
+        val post = FeedPost(
+            title = "Test",
+            textContent = "Content",
+            htmlContent = null,
+            imageUrl = null,
+            linkUrl = null,
+            linkTitle = null,
+            linkDescription = null,
+            linkImageUrl = null,
+            status = "published",
+            publishedAt = null,
+            createdAt = null,
+            updatedAt = null
+        )
+        assertNull(post.imageAlt)
+    }
+
+    @Test
+    fun `FeedPost stores imageAlt`() {
+        val post = FeedPost(
+            title = "Test",
+            textContent = "Content",
+            htmlContent = null,
+            imageUrl = "https://example.com/img.jpg",
+            imageAlt = "Image description",
+            linkUrl = null,
+            linkTitle = null,
+            linkDescription = null,
+            linkImageUrl = null,
+            status = "published",
+            publishedAt = null,
+            createdAt = null,
+            updatedAt = null
+        )
+        assertEquals("Image description", post.imageAlt)
+    }
+
+    @Test
+    fun `PostWrapper includes feature_image_alt in serialized JSON`() {
+        val wrapper = PostWrapper(listOf(GhostPost(
+            title = "Post with alt",
+            feature_image = "https://example.com/photo.jpg",
+            feature_image_alt = "Photo description"
+        )))
+        val json = gson.toJson(wrapper)
+        assertTrue(json.contains("\"feature_image_alt\":\"Photo description\""))
+    }
 }