Responsive CSS Grid Box with shadow effect

How To Install This Code In Your Site -
It's very simple -
Step -1 :
At first setup given css code
Step - 2 :
Now setup given html where you want to show your photo grid.
Step - 3 :
Save Your Data To Finished !
<!--CSS Code Start-->

<style>
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial;
}

.header {
    text-align: center;
    padding: 32px;
}

.row {
    display: -ms-flexbox; /* IE10 */
    display: flex;
    -ms-flex-wrap: wrap; /* IE10 */
    flex-wrap: wrap;
    padding: 0 4px;
}

/* Create four equal columns that sits next to each other */
.column {
    -ms-flex: 25%; /* IE10 */
    flex: 25%;
    max-width: 25%;
    padding: 0 4px;
}

.column img {
    margin-top: 8px;
    vertical-align: middle;
        -webkit-filter: grayscale(100%); /* Safari 6.0 - 9.0 */
    filter: grayscale(100%);
    border:solid 1px black;
}

.column img:hover {
    margin-top: 8px;
    vertical-align: middle;
        -webkit-filter: grayscale(0%); /* Safari 6.0 - 9.0 */
    filter: grayscale(0%);
    transition:0.2s;
    border:solid 1px red;
}


/* Responsive layout - makes a two column-layout instead of four columns */
@media screen and (max-width: 800px) {
    .column {
        -ms-flex: 50%;
        flex: 50%;
        max-width: 50%;
    }
}

/* Responsive layout - makes the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 600px) {
    .column {
        -ms-flex: 100%;
        flex: 100%;
        max-width: 100%;
    }
}
</style>
<!--CSS Code End-->

<!-- HTML Code Start -->
  <div class="row">

<!-- column 1 -->
        <div class="column">
 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

   </div>

<!-- column 2 -->
      <div class="column">
 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>
   
  </div> 

<!-- column 3 -->
      <div class="column">
 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

  </div>

 
<!-- column 4 -->
   <div class="column">

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

 <a href="url" target=_blank>  <img src="web.jpg" style="width:100%" />  </a>

  </div>
</div>
<!-- HTML Code End-->

Image Result: