Blame Geocities
Too many people were using their servers as image-banks for non-geocities websites (thus dumping all the heavy bandwith load onto geocities). So they introduced a feature wherein their servers only dole out images that are internally requested. So there simply isn't any way to put the image on a non-geocities page, although you can link to it like this.
Of course, after it's already in your browser's cache, it'll show up on the habitablezone site as well -- so if you can see it here, Delbert, that's why. :-)
Cheers!
Nathan.