Replace A Link With JS For A Window On Top?

I would like to have the click on an image take the user to a higher resolution image. The user would then click on a Close to close the higher resolution page.

Conventional HTML is like this:

<a href="next_page.html">
<img src="images/my_image.jpg"alt="an image"></a>

Instead, I would like to use an onClick as in

onClick="openWindow('hi_res_image.html','hi_res','toolbar=no,status=yes,scrollbars=no,resizable=no') ;">

with openWindow defined as

function openWindow(theURL,winName,features) {
window.open(theURL,winName,features);
}

[Code]....