Q: Setting wallpaper on secondary display

Hi,

I have 2 screens, a 27 inch thunderbolt and the MacBook Pro 15 inch screen, I (obviously) use the 27 inch one as my main screen.

To set the wallpaper of the 27 inch I simply right-click on any picture and then "Set desktop picture". However when I put a picture on the second desktop (the 15 inch screen) and then click "set desktop picture" it changes the wallpaper of the 27 inch.

Using the "Black Apple --> System Preferences --> Desktop&Screensaver" way isn't practical since I have a huge folder with many wallpapers.

With other words, I would have to search the specifik picture out of all the others manually since it also doesn't sort by the creation date.

I'm using Osx Mavericks.

Anyone knows a solution? I know it's just a minor problem but it's quite frustrating

Thank you for helping.

Finn