diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index d239e48..26ba2e1 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -62,6 +62,25 @@ Notifications:   data/notification-settings.json (editable via UI)
 - **API responses**: Return objects directly, Fastify serializes to JSON
 - **Environment**: Copy `.env.example` → `.env`, secrets must be 10+ chars
 
+## ⚠️ Database Migrations (CRITICAL)
+
+**When adding/modifying database columns, ALWAYS:**
+
+1. **Update schema**: `backend/src/db/schema.ts`
+2. **Create migration file**: `backend/src/db/migrations/XXXX_description.sql`
+   ```sql
+   -- Example: Adding a new column
+   ALTER TABLE medications ADD COLUMN new_column TEXT;
+   ```
+3. **Update journal**: `backend/src/db/migrations/meta/_journal.json`
+   ```json
+   { "idx": X, "version": 1, "when": TIMESTAMP, "tag": "XXXX_description", "breakpoint": false }
+   ```
+
+**Why this matters**: The dev database might get updated manually, but production will break without proper migration files. This causes `SQLITE_ERROR: no such column` errors in prod.
+
+**Migration naming**: `0001_add_strips.sql`, `0002_pack_inventory.sql`, `0003_add_image_url.sql`
+
 ## File Locations
 
 | Purpose | Location |
diff --git a/backend/src/db/migrate.ts b/backend/src/db/migrate.ts
index e2c502f..5485092 100644
--- a/backend/src/db/migrate.ts
+++ b/backend/src/db/migrate.ts
@@ -73,6 +73,21 @@ async function main() {
     console.log("Executing:", stmt.trim().substring(0, 50) + "...");
     await client.execute(stmt);
   }
+
+  // Run migrations for existing databases
+  console.log("Running migrations for existing databases...");
+  
+  // Migration: Add image_url column if it doesn't exist
+  try {
+    await client.execute("ALTER TABLE medications ADD COLUMN image_url TEXT");
+    console.log("Added image_url column");
+  } catch (e: any) {
+    if (e.message?.includes("duplicate column") || e.message?.includes("already exists")) {
+      console.log("image_url column already exists, skipping");
+    } else {
+      throw e;
+    }
+  }
   
   console.log("Database setup complete!");
   process.exit(0);