Looks good and works as advertised!

I do have one remark/suggestion about the configuration, though. If I am not mistaken you end up with 3 possible options that can be configured - "overlay", "overlay + preview tooltip", "overlay + media view tooltip".

You use two switches to control these three options of the thumbnail behaviour on mouse hover, though:

1. Just overlay (old behaviour):

2. Overlay + Preview Tooltip:

3. Overlay + Media View Tooltip:

4. ???:

So to me it seems this fourth switch setting either represents an invalid configuration or one that is already covered by a different state of the switches (probably the same as option 3, "Overlay + Media View Tooltip").

Therefore I think it would be better to have just one configuration element - a pulldown menu with three options or a set of radio buttons, for example - instead of the two separate switches to avoid confusion.

Alternatively, you could keep the switches but deactivate the second switch until the first is set to "true". This seems to be more of a hassle, though, since you would also have to potentially update the value of the second switch (to "false") again when the first is set to "false" again.

Looks very good now! Just two more very tiny suggestions, if you don't mind!