Thumbnailer tries (and fails) to do something with list-dividers
The mechanism that hunts down img's inside of li's tries to work on dividers, but that fails because the has-li-thumb class only pushes "normal" li content over to the right, out of the way of the thumbnail.
On another note, even for normal li's, the thumbnail "hunter" is still crazy overzealous. The documentation used to have a nice simple explanation for when an img would become a thumb. It had to be the first image in the li. This is easy to understand, and let's me write this:
<li>Something<img ...></li>
which I think is a straightforward way to say: Text, FOLLOWED by a little image indicator.
It seems I now have to hide my img in not one, but TWO spans, even when it isn't first. That is, even this creates a thumbnail:
<li>Something<span><img ...></span></li>
I need to do this instead: <li>Something<span><span><img ...></span></span></li>
Wow. Can't we keep it simple? Is making a thumbnail automatically even that interesting of a feature to be mucking with straightforward html that people write?