Removing pictures installed by iTunes

ITunes put every picture from my laptop onto my first generation iPad when I was just trying to do a backup. Most of them don't belong there, they're taking up way too much room, and the iPad refuses to allow me to delete them.

I've heard that the pictures can only be removed by iTunes, from the computer that it was running on when it added the pictures. The problem is, that computer has suffered a hard drive accident that wiped out iTunes, the pictures, and all restore points. I've re-installed iTunes, of course, but it's a new incarnation, with no memory of the original incident. I still have all the pictures on another computer, and can easily put them back onto this computer for iTunes to find, but that's hardly the same thing. Can I still use iTunes to remove the pictures, and if so, how?