Did you try reducing the jpg's quality? As for me, I use Paint to create my thumbnails. Open 800x600 image, resize to 25%, save as blablablaThumb.jpg. If squeezing into 200x200 or less deforms the image too much, I use part of it (without resizing) and write "detail" on the thumb. (Now that I think of it, it isn't every version of Paint that saves jpgs, is it?)