Use the same suggestion I posted earlier but note one thing.
Firebase has multitude of services but Thunkable directly accessing two services only
- Sign In
- Realtime DB
Firebase has storage which you can upload files and images but you will have to do it with your own (Thunkable does not provide access to Firebase storage). So you will need to upload the images to Cloudinary and save the URL to the image in the Realtime DB.