Please correct me if I'm wrong, but in regards to the QuickFix hack; wouldn't it be easier to have the 'popup_image.php' file run a function that searched for "product_b.gif" as opposed to hacking every other file to have it display the "product_s.gif"?
So this way, when creating a product, you upload your thumbnail images at the the happy and and static values of "Small Image Width/Height" which OSC already uses to display everywhere, then when 'popup_image.php' is run, the modified code searches for the file name with an appended "_b".
Again, correct me if I am wrong as I am not a master programmer by any regard, but with my limited knowlege this seems possible.
-Aloha
-C.A.D.