I sent you a separate message going into this in more detail, including about the image tile (I tried it in my HD+). But it sounds like what I was thinking might be it (cached images).
There is no specific refresh interval for the thumbnail as it is manually triggered (or by a Rule or such). I am not making it an automatic thing at this time. So if there was an auto-refresh interval that could be set (like the image Tile) OR the image tile used (depending on what I mention in my message) then it could be handled that way.
