Image Size in widget (news-box)

i want to show a bigger image on the widget area news-box.
To enlarge it that was easy.
is there a way to tell Enfold not to take the size definition “widget” as source for widget images but f.e. “square”.
– yes i can overwrite the widget size definition e.g. by:

add_filter( 'avf_modify_thumb_size', 'enfold_customization_modify_thumb_size', 10, 1 );
function enfold_customization_modify_thumb_size( $size ) {
    $size['widget'] = array('width'=>180, 'height'=>180 );      
    return $size;   
}

but then i had to recalculate all thumbs.
i thought the better way would be to replace the source for the images with “square” on that specific Widget only (in my case newsbox-2 widget.

maybe this here in class-framework-widget.php on line 837:
$image_size = isset($avia_config['widget_image_size']) ? $avia_config['widget_image_size'] : 'widget';

is there a child-theme possiblity to set it to:
$image_size = isset($avia_config['widget_image_size']) ? $avia_config['widget_image_size'] : 'square';