Garrys Mod Background Refuses To Change for me, only sound can be removed

To change Garrys Mod Background, you go to, Steam Apps/ Your user name/ garrys mod/ garrys mod/ materials/ console/ delete or move the original files, i chose to delte and added the new background image, then i went and added the music on thier as well.
Run garrys mod… music is not thier, but the background image is still that default one with the man standing, and thier is only one way to change it and every time i do it resets the folder… why, and how is it doing that when it is DELETED!

[editline]11th November 2010[/editline]

BACKGROUND and music for the main menu it is supposedly to replace is MassEffectBackgroundByKwaX.zip

Try re-naming the texture to background01.vtf, or if you have 16:10 or 16:9 add “_widescreen” after the “01”

Ive got the same problem. The Gmod logo also wont show up. If anyone can help Id really appreciate it.