<!DOCTYPE html>
<html>
<head>
	<title></title>
	<link rel="stylesheet" href="css/uikit.min.css" />
	<link rel="stylesheet" href="css/custom.css">
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
	<script src="js/uikit.min.js"></script>
	<script src="js/components/lightbox.min.js"></script>
</head>
<body>
	<div class="section">
		<div class="uk-grid">
			<div class="uk-width-1-1 ">
				<img src="images/blue.jpg">
			</div>
		</div>
	</div>
	<div class="section">
		<div class="uk-grid">
			<div class="uk-width-1-1">
				<img src="images/black.jpg">
			</div>
		</div>
s</body>
</html>
<!DOCTYPE html>
<html>
<head>
	<title></title>
	<link rel="stylesheet" href="css/uikit.min.css" />
	<link rel="stylesheet" href="css/custom.css">
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
	<script src="js/uikit.min.js"></script>
	<script src="js/components/lightbox.min.js"></script>
</head>
<body>
	<div class="section">
		<div class="uk-grid">
			<div class="uk-width-1-1 ">
				<img src="images/blue.jpg">
			</div>
		</div>
	</div>
	<div class="section">
		<div class="uk-grid">
			<div class="uk-width-1-1">
				<img src="images/black.png">
			</div>
		</div>
s</body>
</html>
Change jpg to png for black
Change jpg to png for black
