How do I get an image to show over the entire page?

[pityocamptes]

I have an image that I have changed the opacity on that I would like to have appear over the site - sort of like a ghosted image. What would be the best way to do this, how do I get the image to always fill the screen no matter resolution or forum index length, etc? Detailed instructions would be greatly appreciated.

Actually, what I would also like to try, and perhaps instructions could be offered for that as well, would be to make the image static, so that the forum/index scrolls, but the image does not move with the rest of the forum... thanks again.

--------------- Added [DATE]1378783397[/DATE] at [TIME]1378783397[/TIME] ---------------

BUMP

Basically I have a custom template that I bought. I like the colors and I want to keep them, but I want to "ghost" an image over it... how? Thanks...