replace standard checkbox with a custom image

I am using the dijit/form/CheckBox to successfully allow a user to toggle the visability of a Variable. I would like to replace the checkbox with a custom image, that would show a highlight if its checked. Do I need to recreate the wheel to get this done, or can I amend what I have thus far?

The checkbox is created with:

function updateAerial_1977Visibility(checkbox) {
    // alert("working");
    if (checkbox.checked) {
        Aerial_1977.show();
    } else {
        Aerial_1977.hide();
    }
}

and the checkbox is displayed in the HTML with:

<input id="Checkbox3" name="mycheck" type="checkbox" 
       data-dojo-type="dijit/form/CheckBox" value="agreed" 
       style="padding-right: 20px;" onclick="updateAerial_1977Visibility(this);" />
<label for="mycheck">77</label>