Comment 13 for bug 733966

Thats because we render the about box from SVG, not a rendered image. Its one of the ways we eat dogfood.
We also encourage the about images to have examples of some of the latest features, which generally results in fairly taxing files to render. The debate on prerendered vs SVG has been had a couple of times, perhaps the trunk should have svg and the release static renders, I dont know.
incidentally if the first time speed issue was down to startup, thats the fonts being cached.