Where is the quality gone... image upload

Hi,

I have used the upload image script below on several sites but now some clients are reporting that their images are loosing a lot of quality when they are uploaded... can anyone see why or suggest anything that i could do to stop the images from loosing quality... thanks in advance

<?php

$default_width = 600;
$default_height = 450;

$thumbnails = true;
$thumb_width = 100;
$thumb_height = 75;

$bg_color = "#777777";
$directory = "images/";

//define a maxim size for the uploaded images in Kb
define ("MAX_SIZE","100000");

//This function reads the extension of the file. It is used to determine if the file is an image by checking the extension.
function getExtension($str) {
    $i = strrpos($str,".");
    if (!$i) { return ""; }
    $l = strlen($str) - $i;
    $ext = substr($str,$i+1,$l);
    return $ext;
}



//This variable is used as a flag. The value is initialized with 0 (meaning no error found)
//and it will be changed to 1 if an error occures.
//If the error occures the file will not be uploaded.
$errors=0;
//checks if the form has been submitted
if(isset($_POST['Submit']))
{
    //reads the name of the file the user submitted for uploading
    $image=$_FILES['image']['name'];
    $file_tmp = $_FILES['image']['tmp_name'];
    $file_type = $_FILES['image']['type'];
    //if it is not empty
    if ($image)
    {
        //get the original name of the file from the clients machine
        $filename = stripslashes($_FILES['image']['name']);
        //get the extension of the file in a lower case format
        $extension = strtolower(getExtension($filename));
        //if it is not a known extension, we will suppose it is an error and will not upload the file,
        //otherwise we will do more tests
        if (($extension != "jpg") && ($extension != "jpeg") && ($extension != "png") && ($extension != "gif"))
        {
            //print error message
            echo '<h1>Unknown extension!</h1>';
            $errors=1;
        }
        else
        {
            //get the size of the image in bytes
            //$_FILES['image']['tmp_name'] is the temporary filename of the file
            //in which the uploaded file was stored on the server
            $size=filesize($_FILES['image']['tmp_name']);
            //compare the size with the maxim size we defined and print error if bigger
            if ($size > MAX_SIZE*1024)
            {
                echo '<h1>You have exceeded the size limit!</h1>';
                $errors=1;
            }
            
            //we will give an unique name, for example the time in unix time format
            $filename = time();
            $image_name = $directory.$filename.'.'.$extension;
            $thumb_name = $directory.$filename.'_s.'.$extension;
                    
            list($width, $height) = getimagesize($file_tmp);

            if($width>$default_width && $height>$default_height)
            {
                //calculate X and Y scale, and default x/y ratio
                $xscale = $width/$default_width;
                $yscale = $height/$default_height;
                $default_ratio = $default_width/$default_height;
                if($xscale > $yscale)
                {
                    $final_height = $default_height;
                    $final_width = $width/$yscale;
                    $crop_x = ($default_width - $final_width)/2;
                    $crop_y = 0;
                } else {
                    $final_width = $default_width;
                    $final_height = $height/$xscale;
                    $crop_x = 0;
                    $crop_y = ($default_height - $final_height)/2;                                          
                }
                
            } else {
                $crop_x = ($default_width - $width)/2;
                $crop_y = ($default_height - $height)/2;
                $final_width = $width;
                $final_height = $height;
              
            }
            
            //create image
            $imageResized = imagecreatetruecolor($default_width, $default_height);

            
            
            
            //create background color
            $red = 100;
            $green = 100;
            $blue = 100;
            //convert from HTML color to RGB
            if( eregi( "[#]?([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})", $bg_color, $ret ) )
            {
                $red = hexdec( $ret[1] );
                $green = hexdec( $ret[2] );
                $blue = hexdec( $ret[3] );
            }
            $fill_color = ImageColorAllocate( $imageResized, $red, $green, $blue ); 
            imagefill($imageResized, 0, 0, $fill_color);
            	      
            if($file_type == "image/pjpeg" || $file_type == "image/jpeg"){
                $imageTmp = imagecreatefromjpeg($file_tmp);
            }elseif($file_type == "image/x-png" || $file_type == "image/png"){
                $imageTmp = imagecreatefrompng($file_tmp);
            }elseif($file_type == "image/gif"){
                $imageTmp = imagecreatefromgif($file_tmp);
            }
            
            imagecopyresampled($imageResized, $imageTmp, $crop_x, $crop_y, 0, 0, $final_width, $final_height, $width, $height);
            

            
            //finally, save the image
            imagejpeg($imageResized, $image_name);
                    
			//create thumbnails
            if($thumbnails==true){
                $imageThumb   = imagecreatetruecolor($thumb_width, $thumb_height);
                imagecopyresampled($imageThumb, $imageResized, 0, 0, 0, 0, $thumb_width, $thumb_height, $default_width, $default_height);
                imagejpeg($imageThumb, $thumb_name);
                ImageDestroy ($imageThumb);
            }
            
            ImageDestroy ($imageResized); 
            ImageDestroy ($imageTmp);  
        }
    }
}

//If no errors registred, print the success message
if(isset($_POST['Submit']) && !$errors)
{
    echo "<h1>File Uploaded Successfully!</h1>";
    echo '<a href="'.$image_name.'"><img src="'.$thumb_name.'"></a>';
}

?>

<!--next comes the form, you must set the enctype to "multipart/frm-data" and use an input type "file" -->
<form name="newad" method="post" enctype="multipart/form-data" action="">
<table>
<tr><td><input type="file" name="image"></td></tr>
<tr><td><input name="Submit" type="submit" value="Upload image"></td></tr>
</table>
</form>

PHP:

 

Try a higher quality, default is 75

bool imagejpeg ( resource $image [, string $filename [, int $quality ]] )

 

Ok cool, thanks, so should i just set the quality to 100

 

what about using this class
http://www.jooria.com/projects/view?project=965

 

You could additionally improve the quality of JPEG images if you use adaptive resizing in some cases (but not for thumbnails) instead of resampling. That could let images look less blurry.