I don't get why there are negative reactions against AMosaic. I actually liked AMosaic, even though it is a bit slow on an 68000 especially when rendering many or big pictures with many colors (but this is mainly the speed of the Datatypes it is using, so IBrowse probably wont help much there).
IBrowse is better because it can decode images progressively. It is not faster but overall experience is better.
I still have the original IBrowse 1.02 package here. If someone is interested I can give it away for free.