How do I play custom WAD files with ZDoom?

[SoldierOfFortune]

I want to take screenshots of a WAD I'm making, but when I run ZDoom it launches me straight to the title screen without letting me select a WAD. How do I get that option?

[Lizardcommando]

You can either use -file command line or drag the wad onto the ZDoom exe

[Phobos]

Get this perfect very simple launcher for Zdoom, Zdoomgl or GZdoom:

http://biohazard.drdteam.org/?p=zdl

It's called ZDL.