Source
File: wp-admin/includes/media.php
function image_media_send_to_editor( $html, $attachment_id, $attachment ) {
$post = get_post( $attachment_id );
if ( 'image' === substr( $post->post_mime_type, 0, 5 ) ) {
$url = $attachment['url'];
$align = ! empty( $attachment['align'] ) ? $attachment['align'] : 'none';
$size = ! empty( $attachment['image-size'] ) ? $attachment['image-size'] : 'medium';
$alt = ! empty( $attachment['image_alt'] ) ? $attachment['image_alt'] : '';
$rel = ( strpos( $url, 'attachment_id' ) || get_attachment_link( $attachment_id ) === $url );
return get_image_send_to_editor( $attachment_id, $attachment['post_excerpt'], $attachment['post_title'], $align, $url, $rel, $size, $alt );
}
return $html;
}