Importing image files makes UE4 crash

Hello. I am using UE4.20.3 and importing an image file (png, tga) I or other people modified after an uncertain date makes UE crash. I have some png files on my computer which I have drawn some time ago, and they import smoothly, but if I edit them in any way (e.g. change white to black), they make UE crash on import. My brother sent me some image files from his computer, and they make my UE crash too. I used Paint for edit, and bro was using Photoshop, Sai and Paint. Any suggestions?

Some further research on the issue. I created a new project in 4.20.3 and tested there. Some edited files import correctly, I was trying to find some sense in which import and which not, but it is absolutely random for me. I had guesses about file names being English and Russian (Russian import better), image size (big images import better) and images being square, but nothing.