Am I right in reading that you've creating a mask to eliminate the background of an image, then imported the image into ghostscript and the mask is covering the image? Did you do the editing in Photoshop (create the mask, etc.)? It sounds like the mask wasn't deleted after eliminating the background, assuming that the mask was a separate channel and not simply painted over the image, and subsequently shows up in ghostscript/ghostview. If this is what you did, and you didn't separate the job but output as a composite, then I can see where the mask would still obscure the image underneath.
Like Wayne said, I didn't know you could edit stuff in ghostview. I do believe you can save or export files out of Ghostscript as .ps or .pdfs, if memory serves me correctly, although all I do, as he does, is open the .ps file in ghostview, check to make sure it looks right on-screen, then run my film.