My favourite way is to let the user select images and share it to my/your app:
https://www.b4x.com/android/forum/threads/retrieve-one-or-multiple-image-s-shared-to-your-app.91612/
Next step: Convert the image to bytes and to a base64 string (strings are easier to handle and can be transfered between platforms) and store it to SQlite.
Better: Save the image to Dir.Internal (without converting it) and create an index in your SQLite db.
Of course it depends on what you are trying to achieve. With this solution no permissions are needed, others need permissions or it will get difficult with newer Android version (accessing folders outside your app).
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