libnetpbm
\"libnetpbm is a C programming library for reading, writing, and manipulating Netpbm images. It also contains a few general graphics manipulation tools, but it is not intended to be a graphics tools library. For graphics tools, Netpbm expects you to run the Netpbm programs. From a C program, the libnetpbm function pm_system() makes this easy. However, since it creates a process and execs a program, this may be too heavyweight for some applications.\"