Alpha Mixer VGA Outputs

I am using the VEEK demo kit with the VIP suite. The VEEK kits demos a single iamge with a header image. I am modifying this code and I am trying to display 4 camera images in the 4 quadrants on the VGA. I am passing in the same camera image 4 times into the Qsys project from the top level verilog file. When I mix the 4 outputs, I always get a black screen. :confused: If I take any of of the 4 inputs and tie it to the clock_video_output the single image works fine.

Are there any examples on how to do create a 4 picture mixer for a VGA image? I have attached my try attempt at mixing 2 images.

Thanks