The first time I synced my iphone with my mac, I didn't realize that all of my photos from iphoto would transfer over to the phone. Now, I need to remove some, as they are taking up too much space. I cannot figure out how to remove them from the phone.

The first time I synced my iphone 4 with my mac, I didn't realize that all of my photos from the iphoto library would transfer over to the phone (more than 3,000). Now, I need to remove some, as they are taking up too much space. I cannot figure out how to remove them from the phone. I tried to uncheck boxes and sync again, but I get a message that there is no room on the iphone. I've read as many articles as I can find, but still cannot manage this. Thanks for any help.