Where a link wraps block elements, including an image, and all elements need to be clickable.
In the use case below, the image resets the stacking order and will always be on top and always be unclickable without a fix.
In my personal use, the div with id "text-wrap" was absolutely positioned on top of its sibling and had no effect on the image's clickability, so long as it had a transparent background.
It seems that if a div has a transparent background, or no explicit background set, then a click filters down through the div to the next element below.
<a> <div id="image-wrap"> <img> </div> <div id="text-wrap"> <p>Some text, etc.</p> </div> </a>
In reality, all this is doing is covering the image with another image (which is also resetting the stacking order), so it doesn't really make the first image clickable. It does, however, make the desired user interaction possible.