Examples of adding a Vignette to Photos with CSS3 Gradients. Code sampled from: http://cl.ly/3Nxc

vignette.css

/* Border & Vignette Setup */
	 
    figure{
      position:               relative;
      display:                block;
      line-height:            0;
      width:                  500px;
      height:                 333px;
      margin-bottom:          2em;
      border:                 1em solid #fff;
      -webkit-box-shadow:     0 .1em .3em rgba(0,0,0,.25);
      -moz-box-shadow:        0 .1em .3em rgba(0,0,0,.25);
    }
    
    figure::before{
      content:                "";
      position:               absolute;
      top:                    -1em;
      bottom:                 -1em;
      left:                   -1em;
      right:                  -1em;
    
    }

    figure::before,
    figure img{
      outline:                1px solid #ccc;    
    }

    figure.vignette img{
      z-index:                1;
      position:               relative;
      display:                block;
      width:                  100%;
      height:                 100%;

    }
    
/* Overlay Method */

    figure.overlay::after{
      position:               absolute;
      top:                    0;
      bottom:                 0;
      left:                   0;
      right:                  0;
      content:                "";
      z-index:                2;
      
      pointer-events:         none; /* "all" disables mouse access to image */

    /* Mozilla Setting */
      background-image:       -moz-radial-gradient(
        center, circle contain, rgba(0,0,0,0) 125px, rgba(0,0,0,.5) 250px
      );

    /* Webkit Setting */
      background-image:       -webkit-gradient(
        radial, 50% 50%, 125, 50% 50%, 250, from(rgba(0,0,0,0)), to(rgba(0,0,0,.5))
        );
    }
    
/* Overlay & Inset Method */

    figure.overlay.inset::after{

    /* Mozilla Settings */
      -moz-box-shadow:        inset 0 0 150px rgba(0,0,0,.75);    
      
    /* Webkit Setting */
      -webkit-box-shadow:     inset 0 0 150px rgba(0,0,0,.75);
    }

/* Mask Method */
    
    figure.mask{
      background-color:       #000;
    }

    figure.mask img{
      -webkit-mask-box-image: -webkit-gradient(
        radial, 50% 50%, 125, 50% 50%, 250, from(#fff), to(rgba(0,0,0,.33))
      );
    }

vignette.html

  <h2>Original</h2>

  <figure>
    <img src="http://farm5.static.flickr.com/4154/5176805856_17bef58c00.jpg" />
  </figure>
  
  <h2>Overlay Vignette Method</h2>
  
  <figure class="vignette overlay">
    <img src="http://farm5.static.flickr.com/4154/5176805856_17bef58c00.jpg" />
  </figure>
  
  <h2>Overlay Vignette &amp; Inset Shadow Method</h2>
  
  <figure class="vignette overlay inset">
    <img src="http://farm5.static.flickr.com/4154/5176805856_17bef58c00.jpg" />
  </figure>
	
  <h2>Mask Vignette Method <small>for Webkit Only</small></h2>
	
  <figure class="vignette mask">
    <img src="http://farm5.static.flickr.com/4154/5176805856_17bef58c00.jpg" />
  </figure>