Magento – How to display Multiple thumbnail images

It turned out to be trivial when I looked into it. The $_image variable is an instance of VarienObject with a label property, so it's just a matter of calling $_image->getLabel().

Here's an abridged section of the final code

foreach ($this->getGalleryImages() as $_image): ?>
    <a href="#" ....>
        <img alt="<?=$_image->getLabel()?> ...

Thank you for the reply.

I already found the answer by myself and I will share it below.

foreach ($products as $product){

    $smallImage = $product->getSmallImage();
    $imagePath  = '/catalog/product' . $product->getImage();

    if( $smallImage == 'no_selection' ){
        echo 'FIXING ' . $imagePath . "\r\n";
        $product->addImageToMediaGallery( $imagePath, array( 'small_image' ), false, false );
        $product->save();
    }
}

But still, I'm curious to know what are the Boolean variables are here.

$product->addImageToMediaGallery( $imagePath, array( 'small_image' ), false, false );