Hi tiny
The quality on those pics looks great, which means you can probably compress them (not resize) & still have a decent looking picture. You can tell by looking at the thumb size they may be a little too big (10k is probably double what you can get away with for a clean thumb sample)
& 500 on one side it pretty much the minimum - I use 640x480 or 600x450 for msot of my free sites & galleries