Hi, this is Porcupine, creating my second tutorial
I made this because the other tutorials on this subject were hard to understand (all except one), and got bad reviews, I hope this is the opposite.
Ok you will need VTF-Edit
You can download from here http://nemesis.thewavelength.net/files/files/vtfedit124-11.exe
Step 1: Now what you do, find any picture that is 1024 x 768 or whatever resolution you play Counter-Strike Source in.
TIP: You could get a screen-shot from in-game
Step 2: Now open VTF Edit. Go to File>Import and navigate to your picture. Click ok to the option box that comes up.
Once its imported (that may take a while) it should look squished sideways, thats ok Go to file>save as and go to
C:/Program Files/Valve/Steam/SteamApps/*accountname*/counter-strike source/cstrike/materials/console (you may need to create that file) and save the file as Background01.vtf
almost identical, but yours is less detailed... this is spam