Addition Scaling Options to Prevent Cropped Images

[bobbytables2048]

I'm using this to display photos and videos over a network share using a Shield TV. I have found that the current image scaling options are limited and I end up with either cropped photos when using Fill or cropped videos when using Center.

Is it possible to add a scaling option which will shrink or enlarge the photo/video adding black bars to the top/bottom or left/right of the image? Black could also be replaced with something matching the image, like a common color or a technique similar to "photo gallery and screensaver" which zooms, blurs and dims the image to use as the background.