how to increase a RAW file size?

Hi all...hoping someone might be able to shed some light on an issue for me. I'm in need of increasing the file size of my image, and I'm at a loss as to how to do this. Traditionally I've always had to do the opposite. I shot the image in NEF (D200) and its 15.5MB. I need to get the file size up to around 50MB. Saving as a TIFF brought it up to 28.7. The agency looking to use the image said; they played around in RAW and was able to get a 50MB file that looked pretty good. I could do the simple thing and just ask them exactly how they did that, but if I'm going to look like a dummy, I'd rather appear as such here There are other images involved and I want to know how they took a base image and increased it so much. Any thoughts? Oh yea, I'm using CS5 extended. Thanks in advance, John