This stuff is really hard. (It might be easier on more consumer-friendly systems, but then you don't get things like a *nix OS (looking at you, windows))

You can easily do it by getting your (w x 2, h) sized wallpaper, and setting the Advanced Background settings to use "Spanned" Picture aspect setting, but how to do deal with multiple monitors that are different sizes?

The manual way:

  • Take a screenshot of your system (Prnt-Sc).
  • Open in your favourite image editing suite
  • Take the left and right sides of your image, and scale them to the non-black areas of your screenshot
  • Save and use.

 

Before:

Original Image

After:

Post Processed

(The setup I have has my laptop lower than my big screen, hence the disparity.

Now I'm thinking, how can I make this automatic using the system settings to resize and shift the smaller image...

Update: This method makes for a HORRIFIC lockscreen. The image that was spanned is then set as a default picture aspect, which ruins the effect :<

lock failure