Color detection

I am in need of a php coder to help me do this script (I think its pretty simple). I have a 300x300 image with a bunch of squares with different colors. I want a script that I can tell it the path/url to the image and the location of the pixel I want it to look at and have it take that color of that pixel and display a 300x300 image with every color that matches the defined pixel is white and the rest are black, as well as list the coordinates of the pixels with the same color as the original. If this makes sense or if you have questions on what I am asking, please email me: pixeldyn@hotmail.com. If you can make this script for me real quick, please send to my email as well. Thanks!

moved