It may be stupid but true, you can link to pictures on Safari's bookmark bar. Simply drag any image (even one that's not hyperlinked) to the bookmark bar and Safari will add it just like a weblink.
[robg adds: At first, I thought this hint would put actual images on the toolbar; it doesn't, of course. But the fact that it works even for unlinked images is interesting. Based on this hint, I tried dragging some text to the toolbar just to see what would happen, but it didn't work.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030214212740999