Well I'm not sure if anyone else had this problem but..
I recently noticed that a few products of mine we're not using
instead they we're opening on their own page.
The only difference between those products that did not work & the ones that did was the File Extension.
For the ones that did work it was just plain .jpg
For the ones that did not work it was .jpeg
Although both are one and the same.
Anyhow, I Changed the extension of my photos that did not work with Easy fancybox from .jpeg to .jpg & this fixed the problem.
I just thought i'd post it here in case anyone runs into the same problem.