Normally, you want "Best Fit and Maintain Aspect Ration (No Clipping), This is great for images larger than your screen but this setting will enlarge a small picture to fill the screen, and it looks quite bad.

Choosing "Center" works for smaller images, but larger ones get cut off...

So, if you have a mix of large and small images, there's currently no single selection that works.

I would suggest: "Best Fit and Maintain Aspect Ration (No resizing if less than Screen Resolution)

Thanks for the consideration. It would save a lot of us from having to manually resize all our wallpapers that are largerthan our resolution, so we can also use ones that are smaller than our resolution.