You have 127 pages of 100 images. About 12,700 images hosted with us going back almost 3 years to 9/12/2006. If you deleted the ones you didn't need you'd probably have less than 50 megs.
Worst case you would have had to click the box to mark all the images on a page 120 or so times and clicked delete. Easily doable in a separate window even while you were doing your normal work. Maybe it would even have taken an hour or two.
Even after all this you would have had $0 of additional image charges.