Use ReadPixel to figure out what color the pixel currently is, and WritePixel to change it to something else.
If you truly have your graphic in an array, you can also change values directly with e.g. MyPictures[15] would be the 16th pixel. It depends if you made it a byte array or an int array as to how you'd read and alter them.
If you truly have your graphic in an array, you can also change values directly with e.g. MyPictures[15] would be the 16th pixel. It depends if you made it a byte array or an int array as to how you'd read and alter them.