I did find A-Prompt (
http://aprompt.snow.utoronto.ca/), which works
pretty well, but is still more manual labor than I was hoping.
Thanks for the link to A-Prompt. I'm sure It'll come in handy as an
addition to my web page validation arsenal.
Could you describe exactly how you'd like your alt text software to do
the matching of the alt text to each image? How exactly do you expect
any program to know what you want to substitute for the alt text? No
matter what you do you'll have to let the program know which alt text
to match to each image, and that will require some manual labor on
your part.
Without knowing more, the best way to match alt text to an image
within an html file is to use a search and replace app with batch
processing capability, such as InfoRapid Search & Replace. But again,
setting up the batch file will require some manual labor.