Question on how message back pics, act when box Isn't transparent?

Before I go through the hassle of such, just to find out it doesn't work, I want to ask it here.

I want the window's skin border to remain, but I want a special backing in certain message boxes.

Will the pic I use for the back, cover the color of the window, while allowing the text to show through?

I think it would work(it really should), I just want to make sure, you know time is precious, and all.

Text appears above pictures. So there should be no problems~

Ok cool thanks(wasn't sure if that was a general rule or a change when set to transparent).