Untitled

dabblet.css

.box {
	width: 400px;
	height: 200px;
	overflow: hidden;
	position: relative;
	margin-bottom: 20px;
}

.box img {
	max-width: 100%;
	display: block;
}

.box-shadow {
	width: 398px; /* 400px - 2px */
	height: 198px; /* 200px - 2px */
	border: 1px solid #000;
	position: absolute;
	top: 0;
	left: 0;
	opacity: 0.25;
}

dabblet.html

<div class="box">
	<img src="http://laughingsquid.com/wp-content/uploads/maru-20090425-125127.jpg">
	<div class="box-shadow" aria="hidden"></div>
</div>

<div class="box">
	<img src="http://laughingsquid.com/wp-content/uploads/maru-20090425-125127.jpg">
	<div class="box-shadow" aria="hidden"></div>
</div>

settings.json

{"view":"split-vertical","fontsize":"100","seethrough":"","prefixfree":"1","page":"all"}