Hand your visitors a magnifying glass to scrutinize your artwork.
Glass active on a thumbnail using Opera on OS X.
Glass active on an image of Bob Floyd rendered using Floyd-Steinberg dithering. The image is kind of big 2400x3122, yet an older G3 Mac running Tiger has no trouble processing it in realtime.
A rather large gallery of rather large images in Firefox on OS X. This page works like a charm on most any browser/platform combination I threw at it.
Microsoft Internet Explorer version 8 (still widely in use) with a solid rim. Note the black lines on both the inside and outside of the rim. This is Microsoft's way of displaying semi-transparent pixels semi-transparently. Note that all other browsers on the Windows platform know how to handle this, so does IE v9.