ladyaeolusia on "How to add a textured bg to an individual post?"

I tried this (an attribute from an old website page) but it didn't work for me:

body {
background-attachment: fixed;
background-image: url("http://---.photobucket.com/albums/-/---/Graphics/paper4.jpg");
background-repeat: repeat;
}

I did something by accident a while back, which DID work, but I felt the code was probably deprecated and so I deleted it. I've also seen advice here about how to change style.css to reflect such a change over the entire site. Yeah, all well and good, I made a note. BUT, to do this on individual pages, as a sort of backdrop to certain images, or what have you...how would I do that?