magento add gallery image list of sku and file name

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
require_once 'app/Mage.php';
Mage::app();
Mage::app()->getStore()->setId(Mage_Core_Model_App::ADMIN_STORE_ID);

$arr = array(
  array("sku"=>"SKU###","file"=>"76763.jpg"),
  array("sku"=>"SKU###","file"=>"76133.jpg"),
  array("sku"=>"SKU###","file"=>"76931.jpg"),
  array("sku"=>"SKU###","file"=>"76703.jpg"),
  array("sku"=>"SKU###","file"=>"77239_1.jpg"),
  array("sku"=>"SKU###","file"=>"77239.jpg"),
  array("sku"=>"SKU###","file"=>"75296.jpg"),
  array("sku"=>"SKU###","file"=>"77261_1.jpg"),
  array("sku"=>"SKU###","file"=>"76422.jpg"),
  array("sku"=>"SKU###","file"=>"76759.jpg"),
  array("sku"=>"SKU###","file"=>"76344.jpg"),
  array("sku"=>"SKU###","file"=>"73661.jpg"),
  array("sku"=>"SKU###","file"=>"77261.jpg"),
  array("sku"=>"SKU###","file"=>"76426_1.jpg"),
);

$importDir = Mage::getBaseDir('media') . DS . 'import' . DS;

foreach($arr as $val){
    $sku = $val['sku'];
    $image = $val['file'];
    $filePath = $importDir.$image;
    $product = Mage::getModel('catalog/product')->loadByAttribute('sku',$sku);
    if(file_exists($filePath)){
    $product->addImageToMediaGallery($filePath, null, false, false);
    echo "done";
    $product->save();
    } else {
        echo $productSKU . " not done";

    }
 echo "<br>";
}

?>