When I sync my iphone, where exactly do my pictures from the iphone go within itunes?

My iphone is full because of several thousand photos taken on it. I do sync my phone, change my apps, manage my music etc. Everything is great except I can’t find my iphone pictures on my computer anywhere. I don’t see that they were backed up to itunes. I don’t see that they were backed up to the computer. Therefore, I never delete off my phone and it’s causing problems. When I sync the phone do they automatically back up to the computer and if so, where?