How to obtain the image ID?

Question

I need a unique ID for each image in Magento store for a special use case.

So I'm trying to figure a way to reliably obtain the product image ID. Is that the $image["value_id"] field?

I tried this:

 foreach ($collection as $product) {
     $imageUrl = (string)Mage::helper('catalog/image')->init($product, 'image')->resize(480);
     $galleryData = $product->getMediaGalleryImages();
     foreach($galleryData as $image) {
         $imageId = $image['value_id'];
     }
 }

Sometimes it works, sometimes it returns null, even when $imageUrl has a valid URL for the image. Is that because an image with a single product photo doesn't have a media gallery?

I need a reliable way to get the image ID for every product that has an image.

Answer 1

I tested on my local Magento 1.9 and I could get $image['value_id'] if there is any image in the product even if it is single image.

I didn't get $image['value_id'] when there is no image in the product, (placeholder image is displayed for the product).

If there is no image in the product, even then you get value for $imageUrl and that will be the image url of placeholder image.