My Code Doesnt Resize Large Images, Please Help.

<?PHP
session_start();
header("Cache-control: private");

function Resize_Image($save,$file,$t_w,$t_h,$s_path,$o_path) {
$s_path = trim($s_path);
$o_path = trim($o_path);
$save = $s_path . $save;
$file = $o_path . $file;
$ext = strtolower(end(explode('.',$save)));
list($width, $height) = getimagesize($file);

if(($width>$t_w) OR ($height>$t_h)) {
$r1 = $t_w/$width;
$r2 = $t_h/$height;

if($r1<$r2) {
$size = $t_w/$width;

}else{
$size = $t_h/$height;


}
}else{
$size=1;
}
$modwidth = $width * $size;
$modheight = $height * $size;


$tn = imagecreatetruecolor($modwidth, $modheight);

switch ($ext) {
case 'jpg':
case 'jpeg':
$image = @imagecreatefromjpeg($file) or die ("Seems to be problem");
break;
case 'gif':
$image = imagecreatefromgif($file);
break;
case 'png':
$image = imagecreatefrompng($file);
break;
}
imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height) or die("he");
imagejpeg($tn, $save, 100) or die ("heheh");;
return;
}

function write_beg($filename, $data){
$handle = fopen ($filename, "r");
$old_content = fread ($handle, filesize ($filename));
fclose ($handle);
$final_content = $data.$old_content;
$handle2 = fopen ($filename, "w");
$finalwrite = fwrite ($handle2, $final_content);
fclose ($handle2);
}


# check to see if form submitted
# if yes, process form variables

# if no, display form

if($_POST["action"]== "Upload Image"){

# define the constant variables

$uploadDir = 'images/'; // main picture folder
$max_height = 600; // largest height you allowed; 0 means any
$max_width = 800; // largest width you allowed; 0 means any
$max_file = 2000000; // set the max file size in bytes
$image_overwrite = 1; // 0 means overwite; 1 means new name
$allowed_type01 = array(
"image/gif",
"image/pjpeg",
"image/jpeg",
"image/png",
"image/x-png",
"image/jpg"); // add or delete allowed image types
$do_thumb = 1; // 1 make thumbnails; 0 means do NOT make
$thumbDir = "thumbs/"; // thumbnail folder
$thumb_prefix = ""; // prefix for thumbnails
$thumb_width = 120; // max thumb width
$thumb_height = 120; // max thumb height
$flat_file = 1; // 1 flat file for data; 0 database
$what_error = array();

# get basic info about uploaded file
$original_name = $_FILES['imagename']['name'];
$original_tmp = $_FILES['imagename']['tmp_name'];
$original_size = $_FILES['imagename']['size'];
$original_type = $_FILES['imagename']['type'];

# do some basic error trapping and cleanup
if($original_size>$max_file) {
//too large, go back to form
array_push($what_error, "File Size Exceeds Limit");
}

if( $original_size<1) {
//no file was uploaded
array_push($what_error, "Please Select A File To Upload");
}

if(!in_array($original_type, $allowed_type01)) {
// wrong file type
array_push($what_error, "File Type Is Not Allowed");
}

if(count($what_error)>0) {
// send to error page
$_SESSION["resultset"] = $what_error;
echo $what_error;
//echo '<meta http-equiv="refresh" content="0;URL=mpg_error.php"> ';
exit();
}

# check to see if file already exists in the folder
# if it exists AND rename option is , create new name
$does_it = FALSE;
$original_name = strtolower($original_name);
if(file_exists($uploadDir . $original_name)) {
if($image_overwrite == 1) {
//rename
while(!$does_it) {
$add_this_name = rand(1,200);
$original_name = $add_this_name . $original_name;
if(!file_exists($uploadDir . $original_name)) {
$does_it = TRUE;
}
}
}
}

# attempt to MOVE the image to its proper location

$uploadFile = $uploadDir . $original_name;
if (move_uploaded_file($_FILES['imagename']['tmp_name'], $uploadFile) ) {
// continue
} else {
// send to error page
array_push($what_error, "error - unknown cause");
$_SESSION["resultset"] = $what_error;
echo "error - unknown cause";
//echo '<meta http-equiv="refresh" content="0;URL=mpg_error.php"> ';
exit();
}

# check to see if image needs resizing and act accordingly

list($original_width, $original_height) = getimagesize($uploadDir . $original_name);
//echo $original_height;

if($max_height<$original_height OR $max_width<$original_width) {
// dimensions are too large - resize
Resize_Image($original_name,$original_name,$max_width,$max_height,$uploadDir,$uploadDir);
echo "image resized done<br>";
}



# check to see if make thumbnails is true
# if yes make and store thumb
$thumb_name = $thumb_prefix . $original_name;

if($do_thumb == 1) {
// make a thumb
Resize_Image($thumb_name,$original_name,$thumb_width,$thumb_height,$thumbDir,$uploadDir);
echo "thumb too";
}


}else{
?>
<html>
<head>
<title>My Photo Gallery Upload Form</title>
<link rel="stylesheet" type="text/css" href="shared_files/textsize.css">

</head>
<body bgcolor="#ffffff" text="#0000a6" link="#0000a6" vlink="#0000a6" alink="#0000a6">

<div style="position: absolute; top: 50px; left: 300px; width:90%; font-size:10pt; padding:10px;filter:shadow(color:gray);"><div style="HEIGHT:250px; border : solid 2px #0000a0; padding : 4px; WIDTH:380px; OVERFLOW:auto; background-color:#fcfcfc; layer-background-color:#fcfcfc; visibility: visible; ">
<form action="<?php echo $PHP_SELF ?>" method="post" enctype="multipart/form-data">
<input type="hidden" name="MAX_FILE_SIZE" value="2000000">
Browse a File to Upload: <br>
<input type="file" name="imagename"><br>
Enter a title for the picture<br>
<input type="text" name="imagetitle" size="40" maxlength="80" value=""><br>
Enter your name<br>
<input type="text" name="artistname" size="40" maxlength="80" value=""><br>
Enter a description for the picture<br>
<input type="text" name="imagedescript" size="40" maxlength="250" value=""><br>
<input type="submit" value="Upload Image" name="action"><br><br>
note: <font color="#ff0080">max file size is: 2megs</font>
</div></div>
</body>
</html>
<?PHP
}

?>