How to Change Facebook Login Screen Background Picture
Go to FACEBOOK Refresh Chrome Extension.
After adding the plugin to Google Chrome, Go to chrome://chrome/extensions/ to access all Chrome extension settings.
Now scroll down until you find the installed extension (FB Refresh), then Click Options just below it.
When you click Options, you'll be redirected to settings page of FB Refresh.
Under Image URL/Upload section you can paste the Image URL that you can
find on Google Image Search or simply Upload an image of you.
After that, you have to Click on Save button in the bottom of the page.
Done! Now you can visit Facebook and notice the new Background that looks very stylish.