how to display a u16 grayscale image on a u32 RGB format

Hello, 

I am currently trying to overlay a u32 RGB image on a u16 grayscale 2D array acquired from a CCD camera. I  order for it to work, we converted the u16 grayscale array into an array of u8 values. Afterwards, this byte was copied into the three bytes corresponding to R, G, B of a u32 RGB image. this allowed us to display the image in grayscale with the overlay in color. However, when we used a LCTF with the camera, there is too much attenuation and we can only see a black image. Probably because the intensity is too low on a sclae of 0-255. 

Here are the images of how we transformed the grayscale into RGB. Does anybody see the problem here?