[kh99]

I think what you want to do is make the image src a template variable, like this:

<div>
	<a href="{vb:raw url}"> <img src="{vb:raw img_url}"
		alt="{vb:rawphrase vbpcsi_add_to_cart, {vb:raw url}}"title="
                  {vb:rawphrase vbpcsi_add_to_cart, {vb:raw url}}" / >
	</a>
</div>

Then your code would set that to the correct url depending on the product and/or whether or not it's already in the cart.