SOIL is a tiny C library used primarily for uploading textures into OpenGL. It is based on stb_image version 1.16, the public domain code from Sean Barrett (found here). I have extended it to load TGA and DDS files, and to perform common functions needed in loading OpenGL textures. SOIL can also be used to save and load images in a variety of formats (useful for loading height maps, non-OpenGL applications, etc.)