> How do I set WinHTTrack so that I can give it a link
> and it'll only follow links surrounded by thumbnail
> images (HTML not Java) and grab the image from the
> linked page?
Can the links from the thumbnails be differentiated somehow?  If so you could
try filters similar to:

-*
+www.example.com/pictures/*.html
+*.gif +*.jpg +*.png

You may also like to read:
<http://httrack.kauler.com/help/Mirror_only_images>