Button which I can choose the exact looks on

All buttons I make have the same grey area around them. I make them with

if (GUI.Button(Rectie, Glowing)) {

Glowing being the texture, Rectie being the rectangle. Why does it have my texture in that standard Unity Button texture? How do I make the button exactly as I which it, that is, only with the "Glowing" texture?

The way it works is that it'll load the background texture from the skin, and use that

Check the documentation for more information: