FreeImage is an open source library project for developers who would like to
support popular graphics image formats like PNG, BMP, JPEG, TIFF, and others
as needed by today's multimedia applications.  FreeImage is easy to use,
fast, multithreading safe, and cross-platform. This port includes both the
original C interface and the C++ wrapper FreeImagePlus.

WWW: http://freeimage.sourceforge.net/