Add meta values to post attachments

<?php
// http://www.gravityhelp.com/forums/topic/attachment-fields-to-edit
// change 122 to your form ID
add_action('gform_after_submission_122', 'add_attachment_meta', 10, 2);
function add_attachment_meta($entry, $form) {

        // Get all images which are attached to this post
        $all_images = get_posts( array(
                'post_type'      => 'attachment',
                'post_mime_type' => 'image',
                'numberposts'    => -1,
                'post_parent'    => $entry['post_id'] )
        );

        // Grab the photographer URL and NAME from the submitted entry
        $ent_name = $entry[32];
        $ent_url  = $entry[33];

        // Loop through all image attachments
        foreach ( $all_images as $image ) {
                update_post_meta($image->ID, 'ent_photographer_name', $ent_name);
                update_post_meta($image->ID, 'ent_photographer_url',  $ent_url );
        }
}