Originally Posted by
SchralphMacchio
That's one reason to host images yourself, so you know that there is no secondary compression. Except when there is no compression then you have to choose your initial JPG compression very well, because you don't want everyone downloading 1MB every time they look at your photo otherwise you pay through the nose!
Anyways, yeah free image hosting sites that re-compress will kill your color depth and sharpness - but you can't blame them for underexposing ;) (bump your ISO and use your histograms)