Probably everyone at least once had situation when they receive a meaningless screenshot with 500 page, a message "Application doesn't work fix it" and 0 info whatsoever.
Here is my tip that saved me a lot of trouble.
I display error id in the center of the screen, large enough so no matter how small and blurry the image is (yes users, send us photos of theirs displays) , It is always easy to ready it so we can start investigation without talking to those monkeys.