vBulletin Background help?

How can I set a wallpaper that is the same size as my forum width and height?

If I use doc_background, then the size of the image varies depending on the size of your monitor.

How do I find out the width and height so that all users see the same size background and it doesn't distort for some?

 

You need to make sure it's fixed, and you can do that via CSS. Google it.

 

Can you find something? I don't know where to begin and I've been googling for an hour or so now.

 

http://davidwalsh.name/css-fixed-position-background-image

 

I have it like that.

url(imageurl); background-repeat:repeat; background-attachment: fixed}

Code (markup):

and i've also tried

url(imageurl); background-repeat:repeat; background-position: fixed}

Code (markup):

I guess what I'm asking, is how do I get the background image to resize itself, or scale itself depending on the browser window size, or the monitor size?