How to add http link on image tag using rails?

I am using ruby 2 and rails 4. I want to add http link into image link in rails. How can I create that?

My codes:

<% for g in @pictures %>                              
   <%= link_to image_tag g.pic_url, class: "img-responsive img-thumbnail" %> 
<% end %> 

I want to create something like below using rails.

<a href="/assets/image_001.jpg"><img src="/assets/image_001.jpg" class="img-responsive img-thumbnail"></a>

Please share with me if any one has any idea.