Image upload errors + quality reduction to push upload

Question

Morning all, creating an ajax upload. problem being i want to error out when image is too large.

Here's my code

PHP Code:

<?php

if(isset($_FILES) && count($_FILES)!=0)
{
    $directory = "./";
    $maxWidth = 2500;

    if(!file_exists($directory))
    {
        mkdir($directory, 0700); // create directory if not exists
    }

    if(!empty($_FILES['fileToUpload']['tmp_name'])) // if file gets posted to iframe
    {
        if(preg_match("#^image/((?:gif)|(?:jpg)|(?:jpeg)|(?:png))$#is", $_FILES['fileToUpload']['type'], $match)) // check for valid files
        {
            $extention = $match[1];
            if(!empty($_POST['fileToUploadName'])) // if user has entered new file name
                $filename = $directory.$_POST['fileToUploadName'].".".$extention;
            else
                $filename = $directory.$_FILES['fileToUpload']['name'].".".$extention;

            list($width,$height)=getimagesize($_FILES['fileToUpload']['tmp_name']); // get height and width

            if(!empty($_POST['width']) && !empty($_POST['height']))
            {
                if(preg_match("#^[0-9]*$#is", trim($_POST['width'])) && preg_match("#^[0-9]*$#is", trim($_POST['width']))) // namke sure input is numerical
                {
                    if($_POST['height'] > $height || $_POST['width'] > $width)
                    {
                        die("Entering height or width values that are larger than the actual image will result in streched and poor quality images. Please alter values.");
                    }

                    $newWidth = $_POST['width'];
                    $newHeight = $_POST['height'];
                }
                else
                    die("Please enter a valid input for height and width");    
            }
            elseif(!empty($_POST['width']) && empty($_POST['height']))
                die("please enter a height if you would like to rezize image");
            elseif(!empty($_POST['height']) && empty($_POST['width']))
                die("please enter a width if you would like to rezize image");
            elseif($width >= $maxWidth || $height >= $maxWidth)
            {
                $larger =  max($width, $height);
                $percent = floor($maxWidth/floor($larger/100));

                $newHeight = (floor($height/100)*$percent);
                $newWidth = (floor($width/100)*$percent);
            }
            // upload file
            if(!file_exists($directory.$filename))
            {
                $uploadedfile = $_FILES['fileToUpload']['tmp_name'];
                if($extention=="gif")
                {
                    if(!$src = @imagecreatefromgif($uploadedfile))
                    {
                        die("Error: Could not create image, image too large");
                    }
                }
                elseif($extention=="png")
                {
                    if(!$src = @imagecreatefrompng($uploadedfile))
                    {
                        die("Error: Could not create image, image too large");
                    }
                }
                else
                {
                    if(!$src = @imagecreatefromjpeg($uploadedfile))
                    {
                        die("Error: Could not create image, image too large");
                    }
                }

                $tmp=imagecreatetruecolor($newWidth,$newHeight);
                imagecopyresampled($tmp,$src,0,0,0,0,$newWidth,$newHeight,$width,$height);

                if($extention=="gif")
                {
                    if(imagegif($tmp,$filename,100))
                    {
                        imagedestroy($src);
                        imagedestroy($tmp); 
                        die("upload complete"); // gif upload complete
                    }
                    else
                    {
                        die("upload failed"); // gif upload failed    
                    }
                }
                elseif($extention=="png")
                {
                    if(imagepng($tmp,$filename,9))
                    {
                        imagedestroy($src);
                        imagedestroy($tmp); 
                        die("upload complete"); // png upload complete
                    }
                    else
                    {
                        die("upload failed"); // png upload failed    
                    }
                }
                else
                {
                    if(imagejpeg($tmp,$filename,100))
                    {
                        imagedestroy($src);
                        imagedestroy($tmp); 
                        die("upload complete"); // jpg upload complete
                    }
                    else
                    {
                        die("upload failed"); // jpg upload failed    
                    }
                }
            }
            else
            {
                die("Error: Filename already exists");    
            }
        }
        else
        {
            die("Error: Please upload only valid image files (.jpg, .gif and .png)");
        }
    }
    else
    {
        die("Error: Please enter file to upload");    
    }
}

?>

The steps i've took to error is:

PHP Code:

if($extention=="gif")
{
    if(!$src = @imagecreatefromgif($uploadedfile))
    {
        die("Error: Could not create image, image too large");
    }
}
elseif($extention=="png")
{
    if(!$src = @imagecreatefrompng($uploadedfile))
    {
        die("Error: Could not create image, image too large");
    }
}
else
{
    if(!$src = @imagecreatefromjpeg($uploadedfile))
    {
        die("Error: Could not create image, image too large");
    }
}

but just dies without error display.

Also does anyone know how using the GD lib i can reduce the size and maybe the quality to push the upload when the file is too large?