The MNG file format exists to provide a way to create animated graphics based on the PNG format. Programs that want an easy way to display and manipulate mng format files can use libmng, which is found here.

Version 1.0.5 of libmng is shipping as of March, 2003. TNGImage 1.2 (the Delphi Wrapper for libmng) shipped in April, 2003.

http://libmng.sourceforge.net/