Restrict media by user

restrict_images_by_user.php

function only_own_attachments($query) {
	global $current_user;
	if(is_admin() && !current_user_can('manage_options') && $query->query['post_type']=='attachment') {
		$query->set('author', $current_user->id);
	}
	return;
}
	
add_action('pre_get_posts', 'only_own_attachments');