I think it is unfortunate that, while many design tweaks are made an the GUI gets a lot of attention from Canonical, this bug seems to remain unresolved. Not the least because users get mixed feedback (setting the desktop wallpaper to one image changes that of the login screen as well, but for the 'slideshow' this doesn't work).
If you don't want the default background of unity greeter, and you want a dynamic/slideshow background for you desktop, you may find a temporary and local fix here: http://askubuntu.com/questions/64001/how-do-i -change-the-wallpaper-in-lightdm/64002#64002 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to unity-greeter in Ubuntu. https://bugs.launchpad.net/bugs/918617 Title: Greeter does not support dynamic wallpapers Status in Unity Greeter: Triaged Status in “unity-greeter” package in Ubuntu: Triaged Bug description: Hi, if you use multiple backgrounds (like one which changes over time), greeter cannot handle it To manage notifications about this bug go to: https://bugs.launchpad.net/unity-greeter/+bug/918617/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

