Is there any way to make sprays work

Is there anywayof making sprays work with gmod, and if not tell me some sprays.

There is a tutorial on how to make sprays here:

It says its for CS:S, but it works with any source game.

But gmod never seems to accept any sprays except for ones with paintbrush icons.

Works 100% fine for me.

How do I convert sprays to VTF?