.customize-control-kirki-radio-image label {
	margin-bottom: 10px;
}
div .customize-control-kirki-radio-image input:checked + label img {
	-webkit-box-shadow: none;
	box-shadow: none;
	border: 4px solid #2B4EFF;
}
div .customize-control-kirki-radio-image input:checked + label::after {
	content: "\f147";
	font-family: dashicons;
	background-color: #2B4EFF;
	position: absolute;
	right: -8px;
	bottom: 4px;
	border-top-left-radius: 2px;
	color: #fff;
	line-height: normal;
	font-size: 20px;
	padding: 1px 0 0 1px;
}

#input_choose_default_header > label {
	background: #fff;
	padding: 3px;
}
div .customize-control-kirki-radio-image #input_choose_default_header input:checked +  label::after {
	right: -5px;
	bottom: 8px;
}

• [F] customizer-style.css
  Delete