Background image in a table not appearing in browsers


I'm making a web page that is table based and I am having trouble with a background image in the table.
I've tried adding the background to a table using CSS.
I've given the table an ID, and created a style rule to apply the appropriate CSS background properties.

Here is the bit of code that I'm using:

#mytable_id {
background-image: url(/assets/images/my_background.png);
background-repeat: no-repeat;

This makes the image appear in the Dreamweaver screen but when I click to Preview it in a browser
window it is not visible. I've tried it in Safari and Firefox and both have the same results.

Any ideas where I'm going wrong?
I put the url of the image in single-quotes. I don't know if this is required by the specification, but I haven't had problems either.

background-image: url('/assets/images/my_background.png');

the other thing that might be going wrong is the availability of the file - is it in the right place relative to the parent file so that the browser will find it? When dreamweaver sets up a preview, does it ensure related resources are properly in place?
Salvador, thanks for the offer and I was gonna take you up on it but luckily Conanite's suggestion worked.
Thanks to both of you for helping out. :icon_notworthy:
Try to avoid using tables, you can easily use lists for tabular data and it's so worth the effort.

you can also shorten the css by doing this

background: url(/assets/images/my_background.png) no-repeat;

you can also put in a colour before the img too, handy if you want to use transparent graphics