The easiest way to visually create a 2d matrix

I am trying to create a 2d matrix with control over the background color and the line color. I want to use it for the background picture file for a pictslider object. Should I be using opengl to achieve this?

Another thing that is confusing me is how cycling 74 measures the height and length of objects in Max. My pictslider is 131. by 112. What do those numbers mean? Because if I use OpenGL I'm not sure how to make the matrix "fit" my pictslider.

Thanks