Does anyone know if and how to compare two JPG photos using code?

I tried filetostr() and while it seemed to work I found that it fails for the following set of commands:

r = filetostr(path to photo 1)
copy photo 1 to photo 2
open photo 2 in a graphic editor (paint will do). Don't make any changes and save it.
s = filetostr(path to photo 2)
wait window r==s returns false!!!

Simply changing re-saving the second photo was enough to make it different.

As always, any assistance is greatly appreciated.

TIA,
Mike