if(isset($_POST["yukle"]) {


    require "include/class.upload.php";
    $image = new Upload($_FILES['resim']);
    if ( $image->uploaded ) {

        $image->file_new_name_body = sha1(md5(date("1YmdHis")));
        $image->allowed = array('image/jpeg','image/jpg','image/gif','image/png');
		$image->mime_check = true;
		$image->no_script = true;
        $image->image_resize = true;
        $image->image_ratio_crop = true;
        $image->image_x = 200;
        $image->image_y = 100;
        $image->image_convert = 'jpg';

        $image->Process( 'upload' );
			
        $image->allowed = array('image/*');
        $image->file_new_name_body = sha1(sha1(date("1YmdHis")));
        $image->file_name_body_pre = 'thumb_';
        $image->image_resize = true;
        $image->image_ratio_crop = true;
        $image->image_x = 100;
        $image->image_y = 100;
        $image->Process('upload/thumb');
		
		
		}

şeklinde sorunsuz ca kullanabilirsin. çalışmaması da imkansızdır.
resize özelliklerini kendine göre ayarlayabilirsin.