in fact I have found the issue, my bad trying to do to many things at once
replace the faulty code with this, again making changes as necessary
<?php echo $row_WADAinventory_tbl['Photo_1_Thumb']?'<a class="thumbnail" href="#thumb"><img src="' . $_SERVER['DOCUMENT_ROOT'] . '/Auto_Dealers/' . $row_WADAinventory_tbl["Dealer_Name"] . '/images/' . $row_WADAinventory_tbl["Inventory_ID"] . '/' . $row_WADAinventory_tbl['Photo_1_Thumb'] . '" border="0" /><span><img src="' . $_SERVER['DOCUMENT_ROOT'] . '/Auto_Dealers/' . $row_WADAinventory_tbl["Dealer_Name"] . '/images/' . $row_WADAinventory_tbl["Inventory_ID"] . '/' . $row_WADAinventory_tbl['Photo_1_Resize'] . '" alt="" border="0" /></span></a>':""; ?>