If you plug your iPad into the new computer using the USB cable, it should show up as just another storage device. Work through the few folders and you'll get to the pictures and then just copy or move them or delete thems as you would any other file. At least that is how it works on my iPad 2. Works the same for the iPhone. I did have to try plugging in multiple times with the iPhone but it worked (pre 5.X OS). No iTunes required.
Last edited by Snake_Pliskinn; 01/03/12 08:53 PM. Reason: Some clarification