Grandma's Graphics hosts a really lovely collection of web-resolution public domain children's artwork, perfect for design projects:
Grandma's Graphics: Unique Images from the Past (via Making Light)
From Harry Clarke to 1890's storybooks, if you're looking for unique images or clipart for use on your web pages or in other design or craft projects you've come to the right place. There's a treasury here at Grandma's Graphics that you probably won't find anywhere else online. Some of these graphics are quite large and take time to load, but be patient, they're worth the wait.