[Plugin: Cimy User Extra Fields] display picture or thumbnail multisite

I am running multisite 3.0.5. I wanted to give my users a sort of per blog sub header image so I created a picture cimy extra field. I want the images to fit the themes left column so I set the max width of the picture to 620pixels. If someone uploads a larger pic a thumbnail is created at the 620pixel size. So now I want to show this pic or thumbnail but only if they uploaded one. this is the code I came up with:

<?php
$thisblog_admin = $current_blog->blog_id;

$user_id_from_email = get_user_id_from_string( get_blog_option($thisblog_admin, 'admin_email'));
$logo_image_url = get_cimyFieldValue($user_id_from_email, logo );
$logo_thumb_url_test = cimy_get_thumb_path($logo_image_url);
      $handle_logo = @fopen($logo_thumb_url_test,'r');
      if($handle_logo !== false){
      $logo_thumb_url = cimy_get_thumb_path($logo_image_url);
      }
      else{
      $logo_thumb_url = $logo_image_url;
      }
	  if(!empty($logo_thumb_url))
echo '<a href="'.get_option('home').'/"><center><img src="'.$logo_thumb_url.'"Our Site Logo/></center>';

?>

It seemed fine. but it creates problems that suck up cpu and memory and crash the server. Is there a better way to show the image, but thumbnail if it exists, but only if there is one ( in IE/Chrome if the user doesn’t upload anything you see the little broken image placeholder)