Opera has added support for longdesc on images in their v10.10b. This is just in time to be made obsolete by new standards.
Still, it would be nice were Gecko, Webkit, and IE to also quickly implement this sensible method.
I used this once, well it
I used this once, well it seemed to make sense, was I bothered that it may have been mostly wasted effort? somewhat, but then there was little alternative to adding a necessary lengthy detailed explanation of the graphic apart that is from a text explanation squirrelled away at the bottom of the page anchored to from the graphic and indented off the screen which I also ended up doing.
Sometimes one really wishes that things were better provided for, it becomes tiresome trying to think of ways of handling things.