Background image different on external display

Hi everyone!

I hook up my MBP to my TV via an HDMI cable, and although it works as expected, I have a strange issue with my background image.

When not using the external display, I have a nice image of 3d cubes as my background. When I plug in the external display, it automatically "reverts" back to an annoying picture I had set previously (this "reverted" background is displayed on both my MBP and on the external display). When I disconnect the external display, my normal cube background comes back.

Anyone else notice this?
Thanks!

When you have two displays connected, you can choose the background for each display. Just go into System Preferences>Desktop & Screen Saver and move your mouse over to the TV screen and there should be an option to change the background image to whatever you want.

Basically you can set a different picture to your MBP's screen and the TV screen.

Hah, really? Nice! Just tried it out, and you are 100% correct.

This works great when you are using it as an extended desktop, but when mirrored, it uses the "TV" picture, and not my "MBP" picture...? How do I set my MBP background as the main one, if that makes any sense?