You can remove the image background within GIMP and make it transparent. You can create drawings on each frame using several tools like paintbrush, text tool, bucket fill tool, smudge tool ...

To create a frame, you’ll first create your design in your favorite software program and export it as a PNG file with a transparent background for each element. This frame is then uploaded to ...

Perhaps you need to set a product photo against a clear white background, or maybe you want to frame a screenshot against a wider image to fit into specific sizing or image ratio requirements.