diff --git a/app/schemas/ai.elimu.content_provider.room.db.RoomDb/30.json b/app/schemas/ai.elimu.content_provider.room.db.RoomDb/30.json
new file mode 100644
index 00000000..430b2e78
--- /dev/null
+++ b/app/schemas/ai.elimu.content_provider.room.db.RoomDb/30.json
@@ -0,0 +1,590 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 30,
+    "identityHash": "0ce90877430c0d369ba13cc370af5cf3",
+    "entities": [
+      {
+        "tableName": "Letter",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`text` TEXT, `diacritic` INTEGER, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "text",
+            "columnName": "text",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "diacritic",
+            "columnName": "diacritic",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "Sound",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`valueIpa` TEXT, `diacritic` INTEGER, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "valueIpa",
+            "columnName": "valueIpa",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "diacritic",
+            "columnName": "diacritic",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "LetterSound",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "LetterSound_Letter",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`LetterSound_id` INTEGER NOT NULL, `letters_id` INTEGER NOT NULL, `letters_ORDER` INTEGER NOT NULL, PRIMARY KEY(`LetterSound_id`, `letters_ORDER`))",
+        "fields": [
+          {
+            "fieldPath": "LetterSound_id",
+            "columnName": "LetterSound_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "letters_id",
+            "columnName": "letters_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "letters_ORDER",
+            "columnName": "letters_ORDER",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "LetterSound_id",
+            "letters_ORDER"
+          ]
+        }
+      },
+      {
+        "tableName": "LetterSound_Sound",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`LetterSound_id` INTEGER NOT NULL, `sounds_id` INTEGER NOT NULL, `sounds_ORDER` INTEGER NOT NULL, PRIMARY KEY(`LetterSound_id`, `sounds_ORDER`))",
+        "fields": [
+          {
+            "fieldPath": "LetterSound_id",
+            "columnName": "LetterSound_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sounds_id",
+            "columnName": "sounds_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sounds_ORDER",
+            "columnName": "sounds_ORDER",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "LetterSound_id",
+            "sounds_ORDER"
+          ]
+        }
+      },
+      {
+        "tableName": "Word",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`text` TEXT NOT NULL, `wordType` TEXT, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "text",
+            "columnName": "text",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "wordType",
+            "columnName": "wordType",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "Number",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`value` INTEGER NOT NULL, `symbol` TEXT, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "value",
+            "columnName": "value",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "symbol",
+            "columnName": "symbol",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "Emoji",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`glyph` TEXT NOT NULL, `unicodeVersion` REAL NOT NULL, `unicodeEmojiVersion` REAL NOT NULL, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "glyph",
+            "columnName": "glyph",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "unicodeVersion",
+            "columnName": "unicodeVersion",
+            "affinity": "REAL",
+            "notNull": true
+          },
+          {
+            "fieldPath": "unicodeEmojiVersion",
+            "columnName": "unicodeEmojiVersion",
+            "affinity": "REAL",
+            "notNull": true
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "Emoji_Word",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`Emoji_id` INTEGER NOT NULL, `words_id` INTEGER NOT NULL, PRIMARY KEY(`Emoji_id`, `words_id`))",
+        "fields": [
+          {
+            "fieldPath": "Emoji_id",
+            "columnName": "Emoji_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "words_id",
+            "columnName": "words_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "Emoji_id",
+            "words_id"
+          ]
+        }
+      },
+      {
+        "tableName": "Image",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`title` TEXT NOT NULL, `imageFormat` TEXT NOT NULL, `checksumMd5` TEXT NOT NULL, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "imageFormat",
+            "columnName": "imageFormat",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "checksumMd5",
+            "columnName": "checksumMd5",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "Image_Word",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`Image_id` INTEGER NOT NULL, `words_id` INTEGER NOT NULL, PRIMARY KEY(`Image_id`, `words_id`))",
+        "fields": [
+          {
+            "fieldPath": "Image_id",
+            "columnName": "Image_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "words_id",
+            "columnName": "words_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "Image_id",
+            "words_id"
+          ]
+        }
+      },
+      {
+        "tableName": "StoryBook",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`title` TEXT NOT NULL, `description` TEXT, `coverImageId` INTEGER NOT NULL, `readingLevel` TEXT, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "description",
+            "columnName": "description",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "coverImageId",
+            "columnName": "coverImageId",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "readingLevel",
+            "columnName": "readingLevel",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "StoryBookChapter",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`storyBookId` INTEGER NOT NULL, `sortOrder` INTEGER NOT NULL, `imageId` INTEGER NOT NULL, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "storyBookId",
+            "columnName": "storyBookId",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sortOrder",
+            "columnName": "sortOrder",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "imageId",
+            "columnName": "imageId",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "StoryBookParagraph",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`storyBookChapterId` INTEGER NOT NULL, `sortOrder` INTEGER NOT NULL, `originalText` TEXT NOT NULL, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "storyBookChapterId",
+            "columnName": "storyBookChapterId",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sortOrder",
+            "columnName": "sortOrder",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "originalText",
+            "columnName": "originalText",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "StoryBookParagraph_Word",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`StoryBookParagraph_id` INTEGER NOT NULL, `words_id` INTEGER NOT NULL, `words_ORDER` INTEGER NOT NULL, PRIMARY KEY(`StoryBookParagraph_id`, `words_ORDER`))",
+        "fields": [
+          {
+            "fieldPath": "StoryBookParagraph_id",
+            "columnName": "StoryBookParagraph_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "words_id",
+            "columnName": "words_id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "words_ORDER",
+            "columnName": "words_ORDER",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "StoryBookParagraph_id",
+            "words_ORDER"
+          ]
+        }
+      },
+      {
+        "tableName": "Video",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`title` TEXT NOT NULL, `videoFormat` TEXT NOT NULL, `revisionNumber` INTEGER NOT NULL, `usageCount` INTEGER, `id` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "videoFormat",
+            "columnName": "videoFormat",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "revisionNumber",
+            "columnName": "revisionNumber",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "usageCount",
+            "columnName": "usageCount",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      }
+    ],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '0ce90877430c0d369ba13cc370af5cf3')"
+    ]
+  }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ai/elimu/content_provider/room/GsonToRoomConverter.kt b/app/src/main/java/ai/elimu/content_provider/room/GsonToRoomConverter.kt
index 363c6edd..7d31498a 100644
--- a/app/src/main/java/ai/elimu/content_provider/room/GsonToRoomConverter.kt
+++ b/app/src/main/java/ai/elimu/content_provider/room/GsonToRoomConverter.kt
@@ -160,6 +160,7 @@ object GsonToRoomConverter {
         // Image
         image.title = imageGson.title
         image.imageFormat = imageGson.imageFormat
+        image.checksumMd5 = imageGson.checksumMd5
 
         // Note: words are stored separately in Image_Word (see ImagesFragment.java)
         return image
diff --git a/app/src/main/java/ai/elimu/content_provider/room/db/RoomDb.java b/app/src/main/java/ai/elimu/content_provider/room/db/RoomDb.java
index 933d32da..98b954c2 100644
--- a/app/src/main/java/ai/elimu/content_provider/room/db/RoomDb.java
+++ b/app/src/main/java/ai/elimu/content_provider/room/db/RoomDb.java
@@ -43,7 +43,7 @@
 import ai.elimu.content_provider.room.entity.Video;
 import ai.elimu.content_provider.room.entity.Word;
 
-@Database(version = 29, entities = {Letter.class, Sound.class, LetterSound.class, LetterSound_Letter.class, LetterSound_Sound.class, Word.class, Number.class, Emoji.class, Emoji_Word.class, Image.class, Image_Word.class, StoryBook.class, StoryBookChapter.class, StoryBookParagraph.class, StoryBookParagraph_Word.class, Video.class})
+@Database(version = 30, entities = {Letter.class, Sound.class, LetterSound.class, LetterSound_Letter.class, LetterSound_Sound.class, Word.class, Number.class, Emoji.class, Emoji_Word.class, Image.class, Image_Word.class, StoryBook.class, StoryBookChapter.class, StoryBookParagraph.class, StoryBookParagraph_Word.class, Video.class})
 @TypeConverters({Converters.class})
 public abstract class RoomDb extends RoomDatabase {
 
@@ -114,7 +114,8 @@ public static RoomDb getDatabase(final Context context) {
                                     MIGRATION_25_26,
                                     MIGRATION_26_27,
                                     MIGRATION_27_28,
-                                    MIGRATION_28_29
+                                    MIGRATION_28_29,
+                                    MIGRATION_29_30
                             )
                             .build();
                 }
@@ -397,4 +398,15 @@ public void migrate(SupportSQLiteDatabase database) {
             database.execSQL(sql);
         }
     };
+
+    private static final Migration MIGRATION_29_30 = new Migration(29, 30) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            Log.i(getClass().getName(), "migrate (29 --> 30)");
+
+            String sql = "ALTER TABLE Image ADD COLUMN `checksumMd5` TEXT NOT NULL DEFAULT ''";
+            Log.i("migrate sql: %s", sql);
+            database.execSQL(sql);
+        }
+    };
 }
diff --git a/app/src/main/java/ai/elimu/content_provider/room/entity/Image.kt b/app/src/main/java/ai/elimu/content_provider/room/entity/Image.kt
index 55323149..3d6cce22 100644
--- a/app/src/main/java/ai/elimu/content_provider/room/entity/Image.kt
+++ b/app/src/main/java/ai/elimu/content_provider/room/entity/Image.kt
@@ -11,4 +11,5 @@ class Image : Content() {
     lateinit var title: String
 
     lateinit var imageFormat: ImageFormat
+    lateinit var checksumMd5: String
 }
diff --git a/app/src/main/java/ai/elimu/content_provider/util/FileHelper.kt b/app/src/main/java/ai/elimu/content_provider/util/FileHelper.kt
index 3ab232ca..738f43a5 100644
--- a/app/src/main/java/ai/elimu/content_provider/util/FileHelper.kt
+++ b/app/src/main/java/ai/elimu/content_provider/util/FileHelper.kt
@@ -36,8 +36,7 @@ object FileHelper {
         }
         val imagesDirectory = context.getExternalFilesDir(Environment.DIRECTORY_PICTURES)
         return File(
-            imagesDirectory, (imageGson.id
-                .toString() + "_r" + imageGson.revisionNumber + "."
+            imagesDirectory, (imageGson.checksumMd5 + "."
                     + imageGson.imageFormat.toString().lowercase(Locale.getDefault()))
         )
     }