WORDPRESS: thumbnail support

function add_custom_sizes() {
    add_image_size( 'xlarge-square-thumb' , 500 , 500 , true );
    add_image_size( 'large-square-thumb' , 340 , 340 , true );
    add_image_size( 'medium-square-thumb' , 150 , 150 , true );
    add_image_size( 'small-square-thumb' , 80 , 80 , true );

    add_image_size( 'large-landscape-thumb' , 280, 210 , true);
    add_image_size( 'medium-landscape-thumb' , 160, 120 , true);
    add_image_size( 'small-landscape-thumb' , 100, 75 , true);

    add_image_size( 'large-portrait-thumb' , 210, 280 , true);
    add_image_size( 'medium-portrait-thumb' , 160, 120 , true);
    add_image_size( 'small-portrait-thumb' , 100, 75 , true);

    add_image_size( 'widescreen-large' , 1000 , 375 , true );

}
add_action('after_setup_theme','add_custom_sizes');