Hmm, that's interesting about the camera I used potentially causing the problem with Photoshop. Now that I think of it, I used a Leica for one photo and a basic point and shoot Canon for the other, then combined the two. I did resize them in Photoshop to the same resolution before my manipulations. I'll try it next time just using my Canon, which I've never had trouble with.

Great detective work indeed!
Thank you again,
Kakes420