Hello! It's definitely possible! Got to the "images" folder that's next to the game file, then go into the "check yourself" folder.
In there, find the image that's currently displayed on your ID card. After you find it, you can replace it with a pic of your choice AS LONG AS it has the same name as the old one and the same format.
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So for example, if the sub3 image is displayed on the ID card and you want to switch it to something else, just delete it, add a new one, name it "sub3" and make sure it's the "jpg" format. It should work!
Ps. You can do this with literally every picture in the game.