Where did my photos go after I backed up my iphone?

I plugged in my iphone to my desktop which has windows 8 and it automatically opened itunes. It asked if I wanted to back up my iphone and I did. It took a while to back it up because I had alot of pictures. When back up was complete I unplugged my iphone. Now I can't find where my photos are. I can see my voice memos in tunes and when I got to edit/Preferences/devices it shows when the back up was but doesn't let me do anything.

It depends on where you chose to back it. In your case you backed up the files to iTunes
You can't physically see the files until you actually restore your iPhone. You can see when your last backup was in settings