thumb quality sucks

[eluser]iniweb[/eluser]
My config:

Code:

$config['image_library'] = 'GD';
$config['create_thumb'] = TRUE;
$config['maintain_ratio'] = FALSE;
$config['width'] = '100';
$config['height'] = '100';
$config['quality'] = '100%';
$config['thumb_marker'] = '_thumb';

Source pic: iniweb.ru/my_pc_2_original.jpg
Thumb pic: http://iniweb.ru/my_pc_2_original_thumb.jpg

How up quality?

P.S. English bad, sorry