How do I put in a custom Titlescreen for my DOOM2 wad? Thread

I have The title screen ready to go in a png file, but I don't know how to add it in. What software should I use and how do I go about doing it?

Thank you

-First of all, you are newbie right, we don't now what game engine you are using in. If case is that you are just don't know how to add .png picture to your forum profile is another story. So be precise next time, please.