definitely use the image tag - simply give each image input tab a unique name - the image is then simply the src="". Also if you are thinking of making these "mouse-over-able" simply use the js term onmouseover="this.src='whateverover.jpg'" and onmouseout="this.src='whateverup.jpg'". A good little tutorial to follow is this one.
Creating Image Submit Buttons in HTML
Cheers