the add_date of an item is already there, so you could just use that. I've got something similar on my store, I can't remember if I had to make any php changes, but in my template I've got:
product.tpl
Code:
{if (($smarty.now)-$product.add_date lt 2592000)}
<div class="stickernewlarge"></div>
{/if}
then my css file adds the image,
hth
__________________
X-Cart version 5 (Previously 3.5-4)
Previous Versions included
BCSE Reward Points Mod
Altered Cart On Sale Mod
Wordpress Plugin
Please don't PM me for support. I help where I can on the forum and your question will more likely be answered there.
Shout me a Coffee!