Just trying to help others and spread the word:
Are you seeing a gap at the bottom of images in WKWebView so that some of the top portion of your image is being cut off? Several of our properties' apps were witnessing this after moving from UIWebView to WKWebView and we were able to find a fix.
solution: apply display:block
to your <img>
elements
Here's a screenshot of what we were seeing with a 320x50 ad cut off because of a gap/margin below the image: https://i.stack.imgur.com/e9VmB.jpg