change size of image on upload? help with code needed.

[dud3r]

I want my code to 1) detect if the image is larger than 50x50px and if it's larger than 50x50 pixels, I want the code to scale the image down to 50x50 or less (50x49, etc, etc as long as it doesn't look stretched out or anything.. I don't really know what that's called). Anyways, I have the upload code here:

require ('rand.php'); //this file generates random number
require ('db.php'); //connect to DB
equire ('config.inc.php');
// Assigning the option variables 
$dir    =    $icon_upload_dir; //located in config.inc.php
$max    =    5000; 
$allowed    =    array("gif"); //allowed filetype

//turns $_FILES['file_field']['name'] to randomnumber.gif
$files_name = (str_rand(7, '123456789').".gif"); //turn

// Check to verify that the file to be uploaded was specified! 
if(!isset($files_name) || $files_name == "none") { 
    echo "No file to be uploaded"; 
    echo "Please try again"; 
    die; 
} 
// Check to verify if the file extension is in the allowable list or not! 
$ext_array        =    explode( "." , $_FILES['file_field']['name'] ); 
$ex                =    $ext_array[count($ext_array) - 1]; 
$ex                =    strtolower($ex); 
if(!in_array($ex,$allowed)) { 
    echo "Incorrect file type!"; 
    die; 
} 
// Converting the size of the file being uploaded to KB from bytes. 
$_FILES['file_field']['size']    =    $_FILES['file_field']['size']/1000; 

// Check to verify that the filesize is less than the allowable filesize
if($size > $max) { 
    echo "The filesize of the file you have uploaded exceeds the maximum allowable file size which is $max KB."; 
} 
// Moving the uploaded file to the specified directory
if(move_uploaded_file($_FILES['file_field']['tmp_name'], $dir."/".$files_name)) { 

//puts url into user field
header("Location: myprofile.php"); //forward to profile after upload
mysql_query("UPDATE users SET u_icon = '".$files_name."', icon_approved = '0' WHERE username = '".$_COOKIE['Username']."'"); //put the name of image into database table (randomnumber.gif)
    die; 
} 
else { 
    echo "The file upload has failed!"; 
    die; 
} 

I'm missing the whole resize code but I don't know what to search for and how to combine it with my upload code.
Thanks in advance for any help.

[Weedpacket]

There's a function called [man]getimagesize[/man]; a check with that would go just after your filesize check (after, because checking the size is a lot faster and easier than checking image dimensions - do the fast and easy checks first and then you don't have to waste time doing the harder checks if the easy ones fail). Another function called [man]imagecopyresampled[/man] can be used to resize the image ("proportionally" is the word you're looking for).