[epitactic]

Yes indeed it could, I haven't tested it but according to Wikipedia, image maps were introduced in HTML 3.2, which was published as a W3C recommendation in 1997 (!), so in principle it should work. Maybe even earlier, there was a supplemental RFC for adding client-side image maps to HTML 2.0 published in 1996: https://tools.ietf.org/html/rfc1980 A Proposed Extension to HTML : Client-Side Image Maps.

Cloud Browser does use a few modern features, a bit of CSS and (optional) JS, but not for anything strictly essential. Again I haven't tested it on any old browsers, but if anyone does I welcome bug reports/patches at https://gitlab.com/epitactic/cloudbrowser/issues.

(I wonder if it would work on NCSA Mosaic? https://news.ycombinator.com/item?id=18428682 - well, Mosaic added the img tag, but not sure if imagemap was yet available.)