A CodePen by Simon Coudeville. Animated CSS ribbon - Another CSS ribbon. Using only the :before and :after pseudo elements to build a rounded shadow corner. Or whatever you would call them.

index.html

<a class="media-image" href="#">
  <div class="image-frame">
    <div class="image-ratio">
      <img src="http://placeimg.com/250/165/arch" alt=""/>
    </div>
    <span class="label label-new">
      Label
    </span>
  </div>
</a>

style.scss

@import "compass";
$darkcolor: #1f2933;
$frame-padding: 5px;

body {
  padding: 2em;
  background-color: hsl(hue($darkcolor),30,95);
  font: normal 100%/1.5 helvetica, arial, sans-serif ;
}

.media-image {
  display: inline-block;
  width: auto;
  
  img {
    display: block;
  }
  
  &:hover {
      
    .label {
      padding-left: 1em;
    }
      
  }
  
}

.image-frame {
	position: relative;
	padding: $frame-padding;
	background-color: #FFF;
	@include box-shadow(0 1px 2px rgba($darkcolor,.5));

	&:after {
		content: '';
		display: block;
		position: absolute;
		top: $frame-padding;
		right: $frame-padding;
		bottom: $frame-padding;
		left: $frame-padding;
		@include box-shadow(0 0 30px rgba($darkcolor,.25) inset);
		z-index: 10;
	}

}

.label {
  position: absolute;
  top: $frame-padding *-1;
  left: $frame-padding *-1;
  display: inline-block;
  padding: 0 0.75em;
  border-radius: 5px 2px 2px 0;
  text-transform: uppercase;
  letter-spacing: .1em;
  font-size: 12px;
  font-size: 0.75rem;
  line-height: 2.35em;
  font-weight: bold;
  color: #6b4e00;
  background-color: #ffc938;
  z-index: 11;
  @include border-radius(5px 2px 2px 0);
  @include box-shadow(0px 2px 0 rgba($darkcolor,.1));
  @include transition(all 0.1s);
  
	&:before {
		content: " ";
		display: block;
		position: absolute;
		width: 5px;
		height: 4px;
		left: 0;
		bottom: -4px;
    background-color: #ffc938;
	}

	&:after {
		content: " ";
		display: block;
		position: absolute;
		width: 5px;
		height: 6px;
		bottom: -6px;
		left: 0;
    background-color: #9e7300;
		@include border-radius(5px 0 0 5px);
	}
  
}