The file extension for graphics that have been reduced using run-length encoding. RLE is a compression method that converts consecutive identical characters into a code consisting of the character and the number marking the length of the run. The longer the run, the greater the compression. It works best with black-and-white or cartoon-style graphics, and is used to compress Windows start-up logos.
Related terms include RLC. Short for Run-Length Coding, a standard coding technique for image or video compression.