Edit a PHP upload script

<?
// Upload settings
$folder = "img/files/"; // Folder in which to store files
$maxlimit = 50000; // Set maximum file limit (in bits)
$allowed_ext = "jpg,gif,png,jpeg,bmp,png"; // Set allowed extensions (split using comma)
$overwrite = "no"; // Allow file overwrite? yes/no

$match = ""; // Clear match variable; for security purposes
$filesize = $_FILES['userfile']['size']; // Get file size (in bits)
$filename = strtolower($_FILES['userfile']['name']); // Get file name; make it all lowercase


if(!$filename || $filename==""){ // File not selected
   $error = "- No file selected for upload.<br>";
}elseif(file_exists($folder.$filename) && $overwrite=="no"){ // Check if file exists
   $error = "- File already exists: $filename<br>";
}

// Check if file size
if($filesize < 1){ // File is empty
   $error .= "- File size is empty.<br>";
}elseif($filesize > $maxlimit){ // File is more than maximum
   $error .= "- File size is too big.<br>";
}

$file_ext = preg_split("/\./",$filename); // Split filename at period (name.ext)
$allowed_ext = preg_split("/\,/",$allowed_ext); // Create array of extensions
foreach($allowed_ext as $ext){
   if($ext==$file_ext[1]) $match = "1"; // File is allowed
}

// File extension not allowed
if(!$match){
   $error .= "- File type isn't allowed: $filename<br>";
}

if($error){
   print "Error trying to upload file:<br> $error"; // Display error messages
}else{
   if(move_uploaded_file($_FILES['userfile']['tmp_name'], $folder.$filename)){ // Upload file
      print "Success! The file has been uploaded: Http://www.freephotohost.co.uk/img/files/$filename";
   }else{
      print "Error! File size might exceed upload limit of server. Try again."; // Display error
   }
}

?>

$extensiones=array("jpeg","jpg","gif");
$num = count($extensiones);
$valor = $num-1;
$bol="n";
for($i=0; $i<=$valor; $i++) {
    if($extensiones[$i] == $var[1]) {
    $bol="y";
    }
}
if ($bol=="n"){
    echo "File type not permited...";
    echo "File types permited are blablablablabla...";
}
if ($bol=="y"){
    //do upload routine mine is 40 lines long ehehe
}