I can't change the default background in any way on my mate desktop. (Maya 13, 64, 3.2.0-23-generic, updated up to today)
(1) right click on desktop and click the optional pictures in "Background" tab; (Whichever you click, no changes at all)
(2) mateconf-tool - desktop - mate - desktop - background - picture_filename
(3) search in my user home folder, tried to change any possible customization files, such as .mateconf/ .mate2/ etc, none works.
I can switch the theme, window border or color scheme will change correspondingly except the background.
Had been trying and searching solutions for a few weeks. Please help me.
-A hopeless compulsive patient who doesn't appreciate the default grey background.