Can I call a cropped image a crop-out?
Solution 1:
You would not use "crop out", most people just use cropped image, or just plain image. Also, since a lot of cropped images are memes, people sometimes use "meme" as a substitute for cropped image. So, your example sentence can be written as:
Everyone's using the cropped image of Bernie to make memes.
Everyone's using that image of Bernie to make memes.
Everyone's using the Bernie meme.