I need to calculate the file size of an image in Wordpress. I retrive the image url with this function:

```
$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' );

```

and with

```
<?php echo $image[0]; ?>

```

I print the image url.

How can I do to retrieve the filesize and to print it?

[Here](http://pastebin.com/Yrm4rcku) is the feed-rss2.php file

Thanks