php thumbnail creation after uploading file

Hi friends what is the best way to create thumbnail on the fly af开发者_Python百科ter uploading an image ?

move_uploaded_file($source, $dest)
//uploaded successfully
//what will be code to generate thumbnail ?

TRY THIS...

function create_img($file_name,$dir,$dest_dir,$maxwidth,$maxheight){
    /* adjust server memory size, file upload size, and post size
    *  htaccess file:
    *  php_value post_max_size 16M
    *  php_value upload_max_filesize 6M
    *  script:
    *  ini_set('memory_limit', '100M'); //handle large images
    */
    ini_set('memory_limit', '100M');
    if(file_exists($dir)){
                $file = "$dir/$file_name";
                if(!file_exists($dest_dir.$file_name)){
                    list($orig_width, $orig_height, $type) = getimagesize($file);
                    //calculate dimensions
                    if ($orig_width > $maxwidth){
                        $height = $maxwidth * ($orig_height / $orig_width);
                        $width = $maxwidth;
                        if($height>$maxheight){
                            $height = $maxheight;
                            $width = $maxheight * ( $orig_width / $orig_height);
                        }
                    }
                    elseif($orig_height > $maxheight){
                        $height = $maxheight;
                        $width = $maxheight * ($orig_width / $orig_height);
                        if($width>$maxwidth){
                            $height = $maxwidth * ($orig_height / $orig_width);
                            $width = $maxwidth;
                        }
                    }
                    else{
                        $width = $orig_width;
                        $height = $orig_height;    
                    }                    

                    $obr_p = @imagecreatetruecolor($width, $height);
                    if ($type == 1) {
                        $obr = @imagecreatefromgif($file);
                        imagecopyresampled($obr_p, $obr, 0, 0, 0, 0, $width, $height, $orig_width, $orig_height);
                        imagegif($obr_p, "$dest_dir/$file_name");
                    }

                    else if($type == 2) {
                        $obr = imagecreatefromjpeg($file);
                        imagecopyresampled($obr_p, $obr, 0, 0, 0, 0, $width, $height, $orig_width, $orig_height);
                        imagejpeg($obr_p, "$dest_dir/$file_name",100);
                    } 
                    else if($type == 3){
                        $obr = @imagecreatefrompng($file);
                        imagecopyresampled($obr_p, $obr, 0, 0, 0, 0, $width, $height, $orig_width, $orig_height);
                        imagepng($obr_p, "$dest_dir/$file_name");
                    }             
                    else{
                        return FALSE;
                    }
                }// if exist
                else{
                    return FALSE;
                }
    }//if exist dir
    else{
        return FALSE;
    }
}//end create_img

I often make use of Symfony's sfThumbnailPlugin; it works well standalone as well as part of the framework. Additionally I usually use the ImageMagick adaptor for the extra filetypes and image operations it can execute.