Magento – image resize in Magento 1.9

From my understanding Magento version 1.8 and less do not zoom the image as such but simply shows the image in full. See app/design/frontend/base/default/template/catalog/product/view/media.phtml

For version 1.9 with the rwd design installed I think it simply resizes the image to width 1200px. See app/design/frontend/rwd/default/template/catalog/product/view/media.phtml

<?php
    $i=0;
    foreach ($this->getGalleryImages() as $_image):
        $_imageUrl = $this->helper('catalog/image')
                          ->init($_product, 'image', $_image->getFile())
                          ->keepFrame(false)
                          ->constrainOnly(true)
                          ->resize(1200);
?>
    <img id="image-<?php echo $i; ?>"
         class="gallery-image"
         src="<?php echo $_imageUrl; ?>"
         data-zoom-image="<?php echo  $_imageUrl; ?>" />
<?php
    $i++;
    endforeach;
?>

Instead of showing excluded images I would change their status exclude to not-exclude programmatically or via database.

If you have access to your database, check catalog_product_entity_media_gallery_value table and see disabled column and you will see few having value as 1, which means they are excluded images.

You can just use sql query to change their status to not-excluded-

UPDATE catalog_product_entity_media_gallery_value SET disabled = 0

This will set all your images (excluded) to non-excluded.

Hope this helps.