Try
<div class="panel-group" id="accordion">
<div class="panel panel-info">
<div class="panel-heading">
<div class="panel-title">
<a class="collapsed" data-toggle="collapse" data-parent="#accordion" href="#first">First</a>
</div>
</div><!--Here heading has to close and collapse has to start-->
<div class="panel-collapse collapse" id="first">
<div class="panel-body">
<img src="images/lebowski-1.jpg" alt="1" />
</div>
</div>
</div>
<div class="panel panel-info">
<div class="panel-heading">
<div class="panel-title">
<a class="collapsed" href="#secound" data-toggle="collapse" data-parent="#accordion">
Secound</a>
</div>
</div>
<div class="panel-collapse collapse" id="secound">
<div class="panel-body">
<img src="images/lebowski-2.jpg" alt="2" />
</div>
</div>
</div>
<div class="panel panel-info">
<div class="panel-heading">
<div class="panel-title">
<a class="collapsed" href="#third" data-toggle="collapse" data-parent="#accordion">Third</a>
</div>
</div>
<div class="panel-collapse collapse" id="third">
<div class="panel-body">
<img src="images/lebowski-3.jpg" alt="3" />
</div>
</div>
</div>
</div>
Demo: Fiddle