Bootstrap two columns layout

You could use the grid layout to give you something like:

 <div class="row">
   <div class="col-xs-6">
     <div>Big Image Goes Here</div>
   </div>
   <div class="col-xs-6">
     <div class="col-xs-12">Little Image #1</div>
     <div class="col-xs-12">Little Image #2</div>
     <div class="col-xs-12">Little Image #3</div>
     <div class="col-xs-12">Little Image #4</div>
   </div>
 </div>

However, you would need to add some padding to the images to give them the white area around them.

The grid layout is explained here: bootstrap grid layout

Here is a JSFiddle example.

Bootstrap is made up of 12 columns in a row. If you want something to display half and half for example, the first element would have a value of six like so: class="col-xs-6"and the second would be the same. To learn bootstrap really well make this site your best friend.

For a demo to your solution click here

Here we have your HTML

<div class="col-xs-7 left">
    <img src="http://placehold.it/300x500">
</div>
<div class="col-xs-5 right">
   <img src="http://placehold.it/200x100">
</div>
<div class="col-xs-5 right">
   <img src="http://placehold.it/200x100">
</div>
<div class="col-xs-5 right">
   <img src="http://placehold.it/200x100">
</div>
<div class="col-xs-5 right">
   <img src="http://placehold.it/200x100">
</div>

CSS

.left{
    float: left; 
}
.right{
    float: right; 
}
div{
    padding: 20px; 
}

There is probably already a class for floating objects in bootstrap I just couldn't remember exactly, so I did it manually.