I can't set background image on Gnome Terminal 3.14
Gnome-terminal's background feature has been removed since 3.8.1. Though I couldn't find this in the official release notes, but this is all known by now and they don't want that feature be back. This is one of the discussion assuring https://bbs.archlinux.org/viewtopic.php?id=161798
Note: This is community Wiki and if anyone finds the reference of this feature removal, add it to the answer by editing this.