How To Add Outer Borders to Images

1.Login to your blogger dashboard--> layout- -> Edit HTML

2.Scroll down to where you see </head> tag .

3.Copy below code and paste it just before the </head> tag.

<style type='text/css'>
 
#outer-borders a img, #outer-borders a  { border: none; float: left; }
#outer-borders a { margin: 3px; }
#outer-borders a:hover { outline: 3px solid #0000ff; }
 
</style>

Note:You can change border color,outline size,margin,... But both outline size and margin must have a same numerical value.

4.Now add your images as below.

<div id="outer-borders">
   
<a href="#"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWQr36QS7wO7vPGgrxswinbNxsmkpK5WOg8H8lGtRQxZYDcVo3fjZMpkhEFCCQ0Je4qguZ-F8MKrVxtffjkGPJeH9nNyGdVosoagDv2OdqmszqphpTLtRkGHEB4XcyfNsi992NoeTf8Z_3/+1+small.jpg" alt="#" /></a>
   
<a href="#"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJZVUo337fbTgtdzP0-KkEE-kv4j2Vg14mOqCSO1ywFY53YhLODypTm43FY7KsPuz6RTkIK_yFdojTRdUXx1UJWSgJntX1z-mQaEHVu2XzK0DTNIF16o-CLw2My6E1LUv8S4miyVCVedm6/+2+small.jpg" alt="#" /></a>
   
<a href="#"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6sHFpXILA5C8ULMrtOB4zX0sZvYYvVD8f_8eJZjypms3Z_UaQEymHwRAChckSqpQRgaZm_uLA6tsflJcKVki9hMuJ_Rfz2XO_996Lt_D-ULMqjtDwSQoDOVXw6n12lX2z-4t7DJEoZyJM/+3+small.jpg" alt="#" /></a>     
  
</div>

You are done.

Demo