well bitmaps are !@#$% huge for one thing, there's better more conservative formats to use, that might be one reasoning.. some people do still have slower connections after all.
Secondly, there's file formats that are accepted, use the ones that are accepted.
Thirdly, phrase stuff nicer, or don't !@#$% about it. I'm tired of everyone tearing Helios apart for it, I do not want to see -anymore- of it.