<a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $this->stripTags($_product->getName(), null, true) ?>" class="product-image">

   <img src="<?php echo $this->helper('catalog/image')->init($_product, 'small_image')->resize($size['width'], $size['height']) ?>" alt="<?php echo $this->stripTags($_product->getName(), null, true) ?>" class="img-responsive"/>

   <?php if(basename($_product->getData('image')) != basename($_product->getData('small_image'))): ?>

   <img src="<?php echo $this->helper('catalog/image')->init($_product, 'image')->resize($size['width'], $size['height']) ?>"

   alt="<?php echo $this->stripTags($_product->getName(), null, true) ?>" class="img-responsive img-two"/>

             <?php endif ?>

            </a>