If what you’re looking for is simply to blur the image edges you can simply use the box-shadow with an inset.
Working example:
http://jsfiddle.net/d9Q5H/1/

Code snippet:
.image-blurred-edge {
background-image: url('https://picsum.photos/200/300');
width: 200px;
height: 200px;
/* you need to match the shadow color to your background or image border for the desired effect*/
box-shadow: 0 0 8px 8px white inset;
}
<div class="image-blurred-edge"></div>