On second thought ... because I hate saying you can't do something :) ... you *should* be able to implement a solution using client-side javascript. in the template file, remove the 'a href' tag from around the image. then add an 'onclick' handler to the img tag for the image. in the click handler, use javascript to execute the 'click' function of the download button. That way when they click on the image it will behave as if they had clicked on the download link.

I'll try and post some sample code in a little bit, but if anyone out there has some js skills and wants to give it a try, feel free to post it here.