Código PHP:
<?php
$sql = "SELECT products_id, products_model, products_price, products_pvd, products_image FROM products WHERE products_id = $product";
$product = mysql_query($sql, $conn);
$product = mysql_fetch_array($product);
$part = $product['products_id'];
$price = $product['products_price'];
$pvd = $product['products_pvd'];
$picture = $product['products_image'];
$sql = "SELECT products_id, products_description FROM products_description WHERE products_id = $desc_id";
$description = mysql_query($sql, $conn);
$description = mysql_fetch_array($description);
$description = $description['products_description'];
if (!($i%2)) {
$color = "BGCOLOR = #FFFF99";
}
else {
$color = "BGCOLOR = #FFFFFF";
}
//Esto es lo que agregaria, pero como no se para que lo necesitas no se
//donde te conviene ponerlo
if (!isset($picture)||($pictura=="")) {
//aca no tiene imagen y haces lo que quieras
}
else {
//aca tenes imagen y haces lo que corresponda
}
echo "<tr><td class='infoBoxContent'>$part</td><td class='dataTableContent'>$category</td><td class='infoBoxContent'>$picture</td><td class='dataTableContent'>$description</td>
<td class='infoBoxContent'>$price €</td>
<td class='dataTableContent'>$pvd €</td></tr>";
?>
Espero que este codigo te ayude a solucionar tu problema
Suerte