transfer pictures from old iphone 3G

Where are the photos? If they are in your Camera Roll of the Photos app on your phone all you have to do is connect the phone to your computer and start whatever application you use to transfer photos from a camera. On a Mac you can use Image Capture or iPhoto. Using the image capture app allows you to copy photos from your Camera Roll to your computer, and delete or keep the photos on your iPhone.

If the photos are not in the Camera Roll they were copied to the phone by syncing with a computer. Read this:

http://www.howtogeek.com/104298/sync-your-ios-device-with-a-new-computer-without -losing-data/