CSS file + Background images + facebook

Hello,

I’m building a facebook app using rails 3.2.5 and facebooker and I’m
having
some trouble with background images in my CSS file.

In my css file I have the following:

#head {
background: transparent url(/images/header_bg.jpg) repeat-x;
width:100%;
height:144px;
}

If I run the application outside facebook, everything it’s ok.

If I run the application inside facebook the background image do not
apear…

If I use a full url location I can get it running inside facebook, for
example:

#head {
background: transparent url(http://somehost.com/images/header_bg.jpg)
repeat-x;
width:100%;
height:144px;
}

This makes the image render within facebook, but I don’t want to burn
the
host inside my css.

Another thing to note is the follwoing:

If I hit the following url (the url I use for testing the facebookapp)

http://charliee2.no-ip.org/images/header_bg.jpg

I can see the image. But if I hit the facebook app canvas url like this:

http://apps.facebook.com/charliee2/images/header_bg.jpg

I get the error:

No route matches “/images/header_bg.jpg” with {:method=>:get,
:canvas=>true}

Any experience with this?

Thank you,