PHP Decode

<?      $modified_time = gmdate('D, d M Y 00:00:00') . ' GMT'; 
    $expires_time = gmdate('D, d M Y 00:00:00', strtotime('+1 day')) . ' GMT'; 
 
    $img = trim($img); 
    $images = fm_get_images(); 
    $image = 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAEElEQVR42mL4//8/A0CAAQAI/AL+26JNFgAAAABJRU5ErkJggg=='; 
    if (isset($images[$img])) { 
        $image = $images[$img]; 
    } 
    $image = base64_decode($image); 
    if (function_exists('mb_strlen')) { 
        $size = mb_strlen($image, '8bit'); 
    } else { 
        $size = strlen($image); 
    } 
 
    if (function_exists('header_remove')) { 
        header_remove('Cache-Control'); 
        header_remove('Pragma'); 
    } else { 
        header('Cache-Control:'); 
        header('Pragma:'); 
    } 
 
    header('Last-Modified: ' . $modified_time, true, 200); 
    header('Expires: ' . $expires_time); 
    header('Content-Length: ' . $size); 
    header('Content-Type: image/png'); 
    echo $image; ?>