Replace checkbox with image button

I am looking for a way to allow for the user to select multiple months, days, hours and minutes where this will be used for scheduling tasks. The easiest way I can imagine doing this is using checkboxes for each element since they have a boolean properly I can use to determine if its selected or not.

In using this approach, I would like to either entire replace the checkbox with an image (different image for checked/unchecked) or just hide the existing image and style the text area to give the effect of an image using CSS.

How can I replace the default checkbox with an image or hide the default checkbox image entirely?

Example: