Magento – Magento Product image on Hover not working

Make sure the attribute manufacturer (and others that you want to list) have the flag Use in product listing set to Yes. After setting the flag you should rebuild your product flat index if Flat catalog is enabled.

Case1:

Rewrite the class Mage_Catalog_Block_Widget_Link and on the rewite class add new funtoin getProductId() on

public function getProductId()
{

if($this->hasStoreId()) {
            $store = Mage::app()->getStore($this->getStoreId());
        } else {
            $store = Mage::app()->getStore();
        }

    if ($this->getData('id_path')) {
            /* @var $urlRewriteResource Mage_Core_Model_Mysql4_Url_Rewrite */
            $urlRewriteResource = Mage::getResourceSingleton('core/url_rewrite');
            $pID = $urlRewriteResource->getProductPathByIdPath($this->getData('id_path'), $store);
    return $pID; 
        }


    return null;
}

Case2:

Rewrite the class Mage_Core_Model_Resource_Url_Rewrite and on the rewrite class add new funtoin getProductPathByIdPath(),which will get product

public function getProductPathByIdPath($idPath, $store)
{
    if ($store instanceof Mage_Core_Model_Store) {
        $storeId = (int)$store->getId();
    } else {
        $storeId = (int)$store;
    }

    $select = $this->_getReadAdapter()->select();
    /** @var $select Varien_Db_Select */
    $select->from(array('main_table' => $this->getMainTable()), 'product_id')
        ->where('main_table.store_id = :store_id')
        ->where('main_table.id_path = :id_path')
     ->where('main_table.product_id IS  NOT NULL)
        ->limit(1);

    $bind = array(
        'store_id' => $storeId,
        'id_path'  => $idPath
    );

    return $this->_getReadAdapter()->fetchOne($select, $bind);
}

this function get Product Id

Case3:

Rewrite the class Mage_Checkout_Helper_Car and on the rewrite class add new funtoin getmyAddUrl().By using this you can get cart url

 public function getmyAddUrl($productId, $additional = array())
    {
        $continueUrl    = Mage::helper('core')->urlEncode($this->getCurrentUrl());
        $urlParamName   = Mage_Core_Controller_Front_Action::PARAM_NAME_URL_ENCODED;

        $routeParams = array(
            $urlParamName   => $continueUrl,
            'product'       => $productId
        );

        if (!empty($additional)) {
            $routeParams = array_merge($routeParams, $additional);
        }


        return $this->_getUrl('checkout/cart/add', $routeParams);
    }