A former student emailed me this morning with exciting news: 2500 Japanese woodblock prints and drawings available free for download
The link he gave was to a blog post by Colin Marshall at Open Culture, and as that post is quite informative, I won't try to emulate it--in fact, there are additional links at the bottom for lots more about Japanese woodblock prints, so check it out.
The Library of Congress does, in fact, have thousands upon thousands of freely downloadable images of many different kinds; while they do try to provide good finding aids, the level of detail varies. This particular collection looks very well organized, so that there are numerous ways for the searcher to locate items. You can narrow things down by artist, period, location shown, and so on. When you find one you want to download, make sure you choose the right file for your purposes; you have the option of several sizes of JPG, a GIF, or a TIF.
The print shown here is a color woodcut by Harunobu Suzuki from 1765 entitled "Semitori" and it shows a woman and a child catching crickets. I chose the 50.7 KB version for this post.