$caption_image_count = 0;

function count_images(){
	global $post;
	$thePostID = $post->ID;
	$parameters = array(
		'post_type' => 'attachment',
		'post_parent' => $thePostID,
		'post_mime_type' => 'image');
	$attachments = get_children($parameters);
	$content = count($attachments);
	return $content;
}
#add_filter('the_content','count_images');

function caption_image_callback($matches) {
	global $caption_image_count;
	$caption_image_count += 1;
	$c = count_images();
	for ($i=1; $i <= $c; $i++) {
		if (is_single()) {
			return '<div class="inum"><span align="center">' . $caption_image_count . '</span></div><div align="left">
			<img src="'.$matches[2].'"'.$matches[3].'></div>';
		} else { 
			return '<img src="'.$matches[2].'"'.$matches[3].'>';
		} 
	}
}    

function caption_image($post_body_content) {
	global $caption_image_count;
	$post_body_content = preg_replace_callback("|<img(.*?)src=\"(.*?)\"(.*?)>|","caption_image_callback",$post_body_content);
	$caption_image_count = 0;
	return $post_body_content;
}

if ( current_user_can('edit_plugins') ) {
	add_filter('the_content', 'caption_image'); }