I have this image

I have this image

http://bpoint.3media.me/wp-content/uploads/2013/10/energ2.jpg

and this code for 533x400

if ( function_exists( 'add_theme_support' ) ) {
add_theme_support( 'post-thumbnails' );
add_image_size( 'slider-big', 533, 400, false);
}

Although cropping is false wordpress crops it

http://bpoint.3media.me/wp-content/uploads/2013/10/energ2-533x400.jpg

why?