diff --git a/app/src/main/java/gallery/memories/NativeX.kt b/app/src/main/java/gallery/memories/NativeX.kt
index b8f8ad7a..d3e9fdd3 100644
--- a/app/src/main/java/gallery/memories/NativeX.kt
+++ b/app/src/main/java/gallery/memories/NativeX.kt
@@ -72,10 +72,16 @@ import java.net.URLDecoder
         }
 
         // Allow CORS from all origins
-        response.responseHeaders = mapOf(
+        response.responseHeaders = mutableMapOf(
             "Access-Control-Allow-Origin" to "*",
             "Access-Control-Allow-Headers" to "*"
         )
+
+        // Cache image responses for 7 days
+        if (path.matches(API.IMAGE_PREVIEW) || path.matches(API.IMAGE_FULL)) {
+            response.responseHeaders["Cache-Control"] = "max-age=604800"
+        }
+
         return response
     }
 
diff --git a/app/src/main/java/gallery/memories/service/DbService.kt b/app/src/main/java/gallery/memories/service/DbService.kt
index cc8b8075..8cd0df7a 100644
--- a/app/src/main/java/gallery/memories/service/DbService.kt
+++ b/app/src/main/java/gallery/memories/service/DbService.kt
@@ -4,7 +4,7 @@ import android.content.Context
 import android.database.sqlite.SQLiteOpenHelper
 import android.database.sqlite.SQLiteDatabase
 
-class DbService(context: Context) : SQLiteOpenHelper(context, "memories", null, 26) {
+class DbService(context: Context) : SQLiteOpenHelper(context, "memories", null, 27) {
     override fun onCreate(db: SQLiteDatabase) {
         db.execSQL("""
             CREATE TABLE images (
@@ -18,6 +18,11 @@ class DbService(context: Context) : SQLiteOpenHelper(context, "memories", null,
                 flag INTEGER
             )
         """)
+
+        // Add index on local_id, dayid, and flag
+        db.execSQL("CREATE INDEX images_local_id ON images (local_id)")
+        db.execSQL("CREATE INDEX images_dayid ON images (dayid)")
+        db.execSQL("CREATE INDEX images_flag ON images (flag)")
     }
 
     override fun onUpgrade(database: SQLiteDatabase, oldVersion: Int, newVersion: Int) {