hi Linux users i have a question, I have Ubuntu 12.04 and I have gnome 3 on their also (i am currently using it) I love it!!!But one thing is wrong when I log out I get the default login screen the purplish red screen thought my wallpaper is the blue striped one (the one on the gnome tutorial website) I really need help!1!

Your Desktop wallpaper is part of your personal theme that loads AFTER you log on.
The login screen is a totally different animal and they SHOULD not look alike.
Your machine is looking (as far as I can tell from what you provide) exactly as intended.

If you want to CHANGE the look of the login, what you need to look up is how to change the background for your GNOME3 login screen. Your personal settings will never touch it. I cannot provide detail myself because 1) I do not change my login screens, and 2) :I do not use gnome3!

With the proper target identified, perhaps someone can point to a man page, how-to document, or other information that pertains.

Look for an item in the control-center called "Login Window" or "GDM settings" or something like that. In Debian, it's called "Login Window." I can't remember what it was called in Ubuntu 11.x.

Alternatively try running /usr/bin/gdmsetup as root. That was the command in Gnome 2.