I'm not sure if this has been suggested before, but I think it would be nice if we could lock in a pair (or more) of wallpapers to be displayed in tandem each time the wallpaper switches. I've found a lot of great multi-monitor wallpapers, but can't find a way to change them randomly while keeping them 'linked' together so that the left image of the pair always appears with the right.

Unless you are trying to mix single pictures with the dual monitor ones, you can just do random within the span one image options. As for mixing them I do believe Jon is working on it.

As a note to him, maybe detecting the resolution of the picture would help? beyond a threshold it would apply to both?