How can I display the checkbox over the images for selection?
This can be done with pure CSS, assuming you have fixed width and height for all images. The trick is setting absolute position for the checkbox then assign bottom and right to zero. Live test case. As for click events, just apply click handler to each checkbox and it will work just fine.. see in this updated fiddle.
What is checkbox example?
A checkbox (check box, tickbox, tick box) is a graphical widget that permits the user to make a binary choice, i.e. a choice between one of two possible mutually exclusive options. For example, the user may have to answer 'yes' (checked) or 'no' (not checked) on a simple yes/no question.