<?php

function gd_get_image1 ($gd_w, $gd_h) {
if ( function_exists( 'get_the_image' ) )
                            global $post, $posts;
                            $get_the_image_as_array = get_the_image( array( 'image_scan' => true, 'format' => 'array' ) );
                            $img1 = $get_the_image_as_array[url];
                            $url = get_bloginfo('url');
                            $img1 = str_replace($url, '', $img1);

                            echo '<a href="'.post_permalink().'">
                            <img src="'.get_bloginfo("template_url").'/thumb.php?src='.$img1.'&w='.$gd_w.'&h='.$gd_h.'&zc=1 />" alt="'.$get_the_image_as_array[alt].'"/>
                            </a>';
}
?>
// the call
<?php function gd_get_image1 (120, 80); ?>