Edit a PHP upload script

<?php

//Upload settings

//Folder in which to store files
$folder = "img/files/"; 

//Set maximum file limit (in bites)
$maxlimit = 50000; 

//Set allowed extensions (split using comma)
$allowed_ext = "jpg, gif, png, jpeg, bmp, png";

//Allow file overwrite? yes/no
$overwrite = "no"; 

//Clear match variable; for security purposes
$match = ""; 

//Get file size (in bites)
$filesize = $_FILES['userfile']['size'];

//Get file name; make it all lowercase
$filename = strtolower($_FILES['userfile']['name']); 

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>";
}

//Split filename at period (name.ext)
$file_ext = explode(".", $filename);

// Create array of extensions
$allowed_ext = explode(",", $allowed_ext);

foreach($allowed_ext as $ext)
{
  if($ext == $file_ext[1])
  {
    $match = "1"; // File is allowed
  }
}

//Assign a unique/random name
$unique = substr(md5(uniqid(rand())), 0, 10);

//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'], $folder.$unique.".".$file_ext))
  {//Upload file
    print "Success! The file has been uploaded: Http://www.freephotohost.co.uk/img/files/".$unique.".".$file_ext;
  }
  else
  {
    print "Error! File size might exceed upload limit of server. Try again."; // Display error
  }
 }
 
?>

elseif(file_exists($folder.$filename) && $overwrite == "no") 
{//Check if file exists 
  $error = "- File already exists: $filename<br>"; 
}

  if(move_uploaded_file($_FILES['userfile']['tmp_name'], $folder.$unique.".".$file_ext))

  if(move_uploaded_file($_FILES['userfile']['tmp_name'], $folder.$unique.".".$file_ext['1']))

$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
}