How do I transfer photos from my IPhone 4 to Itunes on my Dell?

You don't transfer iphotos to itunes. Itunes is not a photo management program.

Pics taken with iphone are imported to your computer as you would from any digital camera.

Photos synced to your iphone from your computer are synced one way - computer to iphone. As they came from your computer in the first place, they should still be there.

Follow these instructions to copy personal photos and videos from iPhone, iPad, or iPod Touch to your computer, http://support.apple.com/kb/HT4083