ART is a proprietary image file format used mostly by the America Online (AOL) service and client software.
The ART format (file extension ".art") holds a single still image that has been highly compressed.
In addition, the AOL client's web browser also automatically served such images in the ART format to achieve faster downloads on the slower dialup connections that were prevalent in those days.
[5] (With later versions of the Graphic Workshop Professional software, an ART plugin from Alchemy Mindworks is required for this support.
[6] As of June 2006 the Internet Explorer browser no longer supported ART files when Microsoft released a security update.