Use this example to change the border radius of the uploaded image for all the Outcome Quiz forms.

add_filter('frm_quiz_outcome_image_border_radius', 'change_quiz_outcome_image_border_radius');
function change_quiz_outcome_image_border_radius() {
	return '100px'; // change 100px
}

Use this example to change the border radius of the uploaded image for a specific Outcome Quiz form.

add_filter('frm_quiz_outcome_image_border_radius', 'change_quiz_outcome_image_border_radius_form', 10, 2);
function change_quiz_outcome_image_border_radius_form( $border_radius, $args ) {
	$target_form_id = 267; //Change 267 to the ID of your form
	if ( $target_form_id === $args['form_id'] ) {
		$border_radius = '100px'; //change 100px
	}
	return $border_radius;
}

Use this example to change the border radius of the uploaded image for a specific Outcome Quiz field.

add_filter('frm_quiz_outcome_image_border_radius', 'change_quiz_outcome_image_border_radius_field', 10, 2);
function change_quiz_outcome_image_border_radius_field( $border_radius, $args ) {
	$target_outcome_id = 1168; //Change 1168 to the ID of your Outcome Quiz field
	if ( $target_outcome_id === $args['outcome']->ID ) {
		$border_radius = '100px'; //change 100px
	}
	return $border_radius;
}