Python create image with continous input

I have a code where an image got converted to B/W. Now I want to build a new image in reference to the original image.

The output of the original image are the X-/Y-coordinates and "1" and "0" for Black and White.

The new image will receive these information but not chronologically. Therefore it must check and provide a negative output if it already has received information about a specific coordinate so that double entries can be avoided.

I haven´t found many similar examples to this; only some examples that are going in the about direction (such as here: http://ift.tt/1hwVK2A).

Does anyone have an idea how to realize that?