How to delete itunes album from computer in phone through itunes?

Ok so one day, I accidentally synced my computer pictures into my phone. I didn't think much of it at the time. But at one point it took so much space that I figured I'd delete either the folder or pictures inside. But turns out the only way was to uncheck the folders on the iTunes page. Ok, but the only tiny but rather big problem was I reset my computer to factory conditions a while ago and the new iTunes won't allow it because the folder isn't on my computer anymore. Is there any other way to delete that folder? I find it kind of a idiotic move that this has to be done through iTunes but then again I'm not surprised, Apple is known to have one big exception on everything that makes it hard to function with its products. Thinking of just getting a samsung or Android at this point.