An idea for a potential new tag called "frame_within_frame", describing images where an alternate version of the image is shown within a frame diegetic to the scene (as an example, on a phone screen). This would not include images which are simply internally framed, such as a doorway in the center of the image.
Some examples:
post #1032503
post #5898251
post #5967526
The name is only tentative, so other suggestions would be appreciated.