iTunes will sync photos from PC to the iPhone. If you have photos in your iPhone camera roll, you need to pull them in. When you plug your phone into the laptop, it usually has a pop up that asks. if you'd like to import photos.
As the other posters have said, first you have to import them to your computer.
1) Connect your phone to your PC. IF iTunes opens, close it!
2) If you have photos in the camera roll on your phone, your PC should recognize your phone as a camera and give you a popup with the option to open your photo editor. If you don't get the popup, open your photo editor manually.
3) Click on the "camera" tab in your photo editor and select get photos, this should give you another window that will allow you to select all photos, or just the ones that you want.
4) After the photos have downloaded to your computer, you can then separate them into folders, witch can then be selected in iTunes and later synced back to your phone.