Oh man. Fair Use is really tricky.
I'd suggest either taking a Powerbook and hooking it up to the web page and teaching a class around the display, or, and this is where Fair Use comes in, xeroxing a similar page in a book or printing out the web page as a handout.
All of these are regularly done but the Fair Use issues come in mostly when lots of pages are copied and handed out, substituting someone else's intellectual property for getting the students to actually pay for the book.
Another possibility is to get the students to go to the web page themselves and study the illustration, or print it out and bring it to class.
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Emily L. Ferguson
mailto:elf@xxxxxxxx
508-563-6822
New England landscapes, wooden boats and races, press photography http://www.vsu.cape.com/~elf/