I'm using windows 7 and I have a slideshow for my desktop background. I have pictures that are all of varying sizes, some are smaller then my screen's resolution, some are the same, and some are much larger.

To look good, smaller wallpapers need to have their picture position set to 'center' (where the picture is centered on the screen and the background color fills up the edges). And the larger backgrounds need to be set to 'fit' (where the picture is scaled down so the entire image is shown on the screen).

I can't seem to figure out a way to have the picture position intelligently change in my background slideshow so that the wallpapers always look good. Any insight?