Impossible. Must be your ISP or your computer.
He has a point, although I think he's referring to the image of the book, which is nearly 200k.I think it's because you're resizing the image in HTML - the actual GIF is 402x584.
Just had a play with it in Photoshop. That image at display size (150x218), comes out at as low as 5k without looking any different to the one you're using:
Basically your version of the image is sucking up 37x more bandwidth than it needs to.