Art Academy is a free Android app that may be of interest to teachers and students of art history. Art Academy is a catalog of more than 4000 paintings. Each painting is linked to some basic information about the artist who created it. Art Academy also provides links to the museum in which each artwork can be found. Through those links you can learn more about the museum, the artist, and the painting.
Art Academy allows you to send the images to your favorite online storage service like Dropbox or Evernote. You can also download images from Art Academy to store on your Android tablet.
One short-coming of the app, as is pointed out in the comments in the Android Market, is that it does not appear include modern artwork. The app also seems to only function in portrait mode on a tablet.