If only selecting/dis-selecting of the checkbox is your requirement then What I would suggest is as under :
Step 1: Place the image and the checkbox inside a block (may it be a div or table)
Step 2: Provide that block relative position with some specific height and width.
Step 3: For checkbox, give it absolute position and set the right and bottom gaps (based on your requirement).
For instance, the code should look like this
<div class="img_block">
<img src="image-path" alt="" />
<input type="checkbox" class="chkbox" />
</div>
<div class="img_block">
<img src="image-path" alt="" />
<input type="checkbox" class="chkbox" />
</div>
And the css for the same is
.img_block {position:relative; width:230px; margin-right:20px; margin-bottom:10px; height:30px;}
.chkbox {position:absolute; right:5px; bottom:3px;}
I hope this suits your requirement.