How do I switch pictures back to my phone after I download them to iphoto?

I think that you have to plug your phone in and go into itunes. When your phone comes up on the left hand side click it it should have the details about apps, music, photos and what not on the main screen. Click on the photo section and select the photo albums you want sync'd with your computer. If it's anything like an iPod touch the photos won't sync with the iPhone if you don't have any selected.

Hope this helps.