[Princeton]

you cannot hide the path to an image

to add a background image to a post use CSS

if you want to use a different image for each post I suggest using inline CSS ie.

style="background-image:url(my/image/goes/here.gif) center center"

if you want one image for all posts ..
create a new class and add it to your stylesheet via Style Manager / Main CSS

you can then prepend the new class with the alt1 selector of the postbit
ie. class="alt1 newclass"