Looks like its an AOL modified browser with only the .art extension.
I don't use AOL, so I don't no much, but if AOL provides ways to unmodify IE, plzz do that.
Launch AOL. This can be done on-line or off-line. Click on My AOL, then choose Preferences, then choose WWW. There you will find three choices for graphics; No graphics, Compressed graphics, Uncompressed graphics. Choose the Uncompressed graphics. Now the whole problem of the .art files will be gone. If you download a GIF or a JPG image, it will be on your hard drive as the GIF or JPG image, and be readable and usable in the normal fashion.
Try aboves and post back.
In the land of Seatle, by the fires of Microsoft, the dark lord Bill Gates forged in, secret, a master OS, to controll all PCs.
And into this OS he put his greed, his malice and his will to dominate all computer media.
One OS to rule 'em all.