max is 600 up it or use smaller pics

$maxWidth = (int)getParam( 'group_img_width' ); //600
$maxHeight = (int)getParam( 'group_img_height' ); //600
$maxWidth_ = (int)getParam( 'group_img_tmb_width' ); //600
$maxHeight_ = (int)getParam( 'group_img_tmb_height' ); //600