getMedia Image By product Id in magento

  $_product = Mage::getModel('catalog/product')->load($product->getId());

  $product->getMediaGalleryImages();        // This returns nothing
  $_product->getMediaGalleryImages(); 

<?php

$model = Mage::getModel('catalog/product') //getting product model

$_product = $model->load($productid); //getting product object for particular product id

echo $_product->getShortDescription(); //product's short description

echo $_product->getDescription(); // product's long description

echo $_product->getName(); //product name

echo $_product->getPrice(); //product's regular Price

echo $_product->getSpecialPrice(); //product's special Price

echo $_product->getProductUrl(); //product url

echo $_product->getImageUrl(); //product's image url

echo $_product->getSmallImageUrl(); //product's small image url

echo $_product->getThumbnailUrl(); //product's thumbnail image url  

?>