http://www.jpegcameras.com/libjpeg/libjpeg.html

this one is really good example 🙂
http://andrewewhite.net/wordpress/2008/09/02/very-simple-jpeg-writer-in-c-c

this one also 🙂
http://www.cppblog.com/socketref/archive/2006/03/02/3623.aspx