Itunes says I have 347 photos but there are only 72 photos on my iPhone?

I'm trying to clear up iphone space. I have 72 photos on my camera roll and yet the photos from iTunes take up 3.7 GB and itunes states I have 347 photos. I already synced an empty photo folder to my iPhone but somehow the photos from iTunes still end up there. And, I can't find the 347 photos anywhere on iTunes or my computer? What's up?! Or are the photos stored on another computer since I have 3 comps authorized for my iTunes account? Btw, I don't link photostream to my iPhone.

Adding on, I can't find the 347 photos in my iphone too. Essentially, 3.7GB of space is taken up in my phone without me being able to see the photos. WHAT THE ****.