ImageMapType persist previous zoom-level tiles?

[Tim Elliott]

I have a fully functioning implementation of ImageMapType with my own tile server. The question I have is I would like to add additional zoom levels however I do not have any further high res imagery -- However for my users that is fine. They'd rather have a blurry and less precise image than being stuck at say zoom level 7 when they'd really like to be at zoom level 8.  Right now my only option is to simply create the tiles for that additional zoom level.

However when you initially zoom-in to a new level, before maps loads the new tiles, it shows the existing tiles just at 2x the size. However when the next tiles yield a 404, the temporary tiles now disappear just showing the background.  So my question is this:

Is there a way to have Maps keep zoom level 7 imagery when I go to zoom level 8? Just let the browser do the auto-scaling and don't release those tiles. I'm just wasting a lot of bandwidth sending over new "higher resolution" tiles that their browser had already auto-scaled to 200%.

[Bob]

I was wondering if you (or anybody else) ever found out how to do this? 

I am facing the same issue.

Thanks in advance.