The biggest problems with this stuff is one imagic magic is VERY slow at recompressing. We tried it and it was way to slow to be usable on a decient size freehost. Also the images actually crash image magick alot of the time.
The images can be real small images with garbage attached on the end, or very large images. We have seen both. Also they can be in gifs or jpegs.
btw the compressing at 99.9% would actually increase the size of all your other images, so thats not a good idea
