Semi-transparent color masking

dabblet.css

/**
 * Semi-transparent color masking
 * (answer to question)
 */

.img-wrapper {
	position: relative;
	float: left;
	overflow: hidden;
}

.img-wrapper:after {
	content: '';
	position: absolute;
	top: 0; right: 0; bottom: 0; left:0;
	
	/*bigger than half the element is */
	border-radius:999px;
	box-shadow: 0 0 0 100px rgba(255,255,0,.5),
		0 0 0 10px rgba(255,255,0,.5) inset;
}

dabblet.html

<div class="img-wrapper">
	<img src="http://placekitten.com/150/150" />
</div>

settings.json

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