I wrote a script that will probably interest web developers / designers. It adds a service to Finder so that you can right-click on image files (or use the actions button) and generate the HTML image tags for them.
It only works on Snow Leopard, since it uses Snow Leopard’s new Services features.
You can download it here (be sure to read the Readme file!):
It should also appear on automatoractions.com in a day or two.