Image upload and scaling

Hi, I am trying to make a util whereby ppl can upload their own images to my server for me to automatically display them. The below code works fine, but I have the following problem. It only works fne if everyone complies to a standard of a set width and height for the image. This is not always possible, so I'm looking for a way to accept the image in any form they have and then to scale it to fit within an acceptable height/width range. This I need help with, so if someone could hep me ( at the hand of my current code) I would be very pleased. Thanks Petre below my code snippet <?php if ($submit) {

       if ($file != "none") {

               $current_time = time();
               $location_pic = "/home/www/imgs/listings/".$current_time.$file_name;
               $url_pic = "http://www.website.co.za/imgs/listings/".$current_time.$file_name;
               copy ($file,$location_pic);
               $db= mysql_pconnect("localhost","db_user","db_password");
               mysql_select_db("DB_NAME",$db);
               $sql = "update table set location_pic = \"$location_pic\", url_pic = \"$url_pic\" where id = \"$id_pic\" ";
               $result = mysql_query($sql);

       }
       echo "Picture Uploaded! Thank You!<br>";
       echo "Below is a preview of how your logo will look. If it displays incorrectly, adjust your image with an image editor of choice and upload again.<br>";
       echo "<img src=\"$url_pic\" width=\"350\" height=\"150\">";

}else { echo " Please use this form to upload image.<br><br><br> <form method=\"post\" action=\"$PHP_SELF\" enctype=\"multipart/form-data\"> Logo Location : <input type=\"file\" name=\"file\"><br><br><br><br>Please Note!Your image must be smaller than 50KB! <input type=\"hidden\" name=\"MAX_FILE_SIZE\" value=\"50000\"> <input type=\"hidden\" name=\"id_pic\" value=\"$id\"><br> <input type=\"submit\" name=\"submit\" value=\"submit\"> ";} ?>