Since version 13, Firefox has the new about:newtab page, which is great...but you can't change the background! Customize about:newtab is an add-on that solves that.
Now you can change the background color and/or choose an image.
Also, you can choose to make about:newtab your home page.
Acces easily to the preferences with a cog icon in the about:newtab page.
· Mozilla Firefox
What's New in This Release: [ read full changelog ]
· Preferences were added to select the number of rows and columns