WikiArt - The Encyclopedia of Fine Art
Responsinator - Designed to test responsive websites on different devices.
ArtMajeur - +1 Million original artworks, Free Shipping Worldwide, Low prices guaranteed, 14 days return: buy all the art you love on Artmajeur!
Responsive Viewer - View multiple screen dimensions in one view
Saatchi Art - Online art platform for buying, selling and discovering art.
Multi Screen Test - Test your site at different screen resolutions & devices.