You guys know, my business is digital pathology, and the basic unit of digital pathology is the "digital slide", a digitized version of a microscope slide. One of the cool things you can do with digital slides is to embed them in web pages. This doesn't require any client-side plug-ins or other software, it can be done in any standard web browser, like this:
The + and - buttons on the toolbar let you zoom in and out, and the arrows let you pan around. You can also navigate by dragging the little red rectangle around on the thumbnail image, or just by dragging the image itself. Pretty cool, eh?
You might never need to do this yourself, but just in case you do or want to know more, I just posted about Putting digital slides in web pages on the Aperio blog. You're welcome!