I used to use a jpeg spray in l4d when playing with Michelle and Jimmy ages ago but could'nt get them to work in the current version of the game.....it now has to be a tga file like our current SSDi sprays so they will work fine.
If you want to do this just put your SSDi tga spray or any tga spray in the logos file
steamapps/common/left 4 dead/left 4 dead/materials/vgui/logos
If there is'nt a logos file already in the vgui folder just create one.
