PDF thumbnail of first page

[Scooby08]

I'm trying to create a thumbnail of just the first page of a pdf and have been unsuccessful.. Here is the code that works perfectly, but creates thumbnails for all pages..

 

<?php
$new_file_name = preg_replace("/[^a-z0-9\.]/i",'_',$_FILES['uploaded_image']['name']);
exec("/usr/local/bin/convert \"".$_FILES['uploaded_image']['tmp_name']."\" -colorspace RGB $supplied_dir/". $new_file_name . "");
$patterns = array ('/[^a-z0-9\.]/i','/pdf/','/PDF/');
$replace = array ('_','jpg','jpg');
$new_file_name_image = preg_replace($patterns,$replace,$_FILES['uploaded_image']['name']);
exec("/usr/local/bin/convert $supplied_dir/$new_file_name -thumbnail '150x150' $supplied_dir/.thumbs/viewer_150x150_$new_file_name_image");
?>

 

I read that I can add a zero in brackets somewhere after the pdf file, but this doesn't seem to work..

 

<?php
exec("/usr/local/bin/convert $supplied_dir/$new_file_name[0] -thumbnail '150x150' $supplied_dir/.thumbs/viewer_150x150_$new_file_name_image");
?>

 

What am I missing here?