The process of finding an image in an image is called "Image Cross Correlation". I can tell you that that is not an easy task. A fast way is 2D FFT correlation. Hmmm......

http://paulbourke.net/miscellaneous/correlate/

http://www.dspguide.com/ch24/6.htm

An other thing is that such methods will not say true or false. You need a multi stage detection process to refine.