Well sure that's for something normal, but for the all-powerful vectors I can render at literally whatever I want. Technically the initial image was at 802x802 at 90dpi, but that doesn't actually matter.
What I've ended up doing is using the 90dpi render for posting, included a 180dpi version in the download and linked through the 90dpi image, made a widescreen image as a video thumbnail, and then rendering one last version at 600x600 and running it through PNG Gauntlet to keep it as small as possible within the files.