Throughout most of history, it has been incredibly difficult to see the world's greatest works of art. But the Internet has the potential to change that. Some of the museums that hold the physical copies of art, have been loath to digitize their collections. So while it might be possible to visit the museum gift shop from your home, you'd have to pay airfare and actually go there to view any of its art.
That's beginning to change. The Louvre offers a (somewhat disorienting) digital tour of its facilities. And now the Metropolitan Museum of Art is releasing digital versions of almost all its art as well. Not just low resolution thumbnails: more than 340,000 high resolution images free for download.
The art is intended for non-commercial use -- if you're trying to make money off of it, you still have to pay a licensing fee. But for students, educators, and the general public, it's a treasure trove of incredible value. You can turn one of the 500 Picassos into a wallpaper. Not just for your computer, but for your home.
Go ahead and browse the collections. Anything marked OASC is yours for the taking.