Suppose we want to compare two binary files image.png and image-win.png. First run the following command to convert them to hex files:
$ xxd image.png > image.hex
$ xxd image-win.png > image-win.hex
Then you can use your favorite editor to compare them. For example kdiff3:
$ kdiff3 image.hex image-win.hex
You can use hexdump instead of xxd.
Use DHEX program:
$ dhex image.png image-win.png
Use VBINDIFF program:
$ vbindiff image.png image-win.png