Originally Posted by surfaces
Compress your images with YSlow it's compressing the images more than the google tool.
And use if possible png files.
Or you can create a forwarder to a image hoster and upload your images there. abload.de is a very fast imagehoster but server location is germany.
I've heard quite a bit of suggestions to use png above all, but I've noticed png being about the same size as jpg and in some cases jpg was smaller than png.
So I'm not quite sold on png being the better format to use. The only benefit of using png I see, is the ability to use transparency in the image.
For quality and transparency, I would certainly choose png over gif.