Pitak, reBOOT just uses the standard mail templates (from ideal responsive), so it may be a v4.6.4 bug.
Check that the product actually has an image associated with it.
You could replace that code with...
Code:
<td style="border: 1px solid #EFEFEF; width: 10%; padding: 5px; text-align: center;">
<a href="{$catalogs.customer}/product.php?productid={$products[prod_num].productid}"><img src="{$http_location}/image.php?type=T&id={$products[prod_num].productid}"></a>
</td>