<style>
.image-blurred-edge {
    background-image: url('https://64.media.tumblr.com/79a04b5e2e9b8f297bf8c0467444c4f5/tumblr_n4wzplYfWD1r3hi20o1_500.png');
    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;
}
</style>
<div class="image-blurred-edge"></div>