OK. Now where exactly did they take these photos? Photo Booth on the iPad or Photo Booth on the Mac?
If the photos were taken with Photo Booth on the iPad, they will be saved to the camera roll album in the photos app. All photos taken with the iPad camera end up in the Camera Roll on the iPad.
If the photos were taken in Photo Booth on your Mac, then they synced the photos to the iPad - maybe it was done without your knowledge - and the only way that the photos can be removed is by unselecting those photos in the Photos Tab of iTunes and then syncing in order to remove them.
You cannot remove synced photos directly on the iPad. You have to unsync them to remove them.