Tiny MCE caching?

When using the Insert/Edit Image button and then through the Advanced tab enabling the Swap Image functionality for image rollovers, is there any kind of Image caching that gets performed so that the rollover images doesn’t have to wait to load?

If there is a pre-caching where does this get performed. Just looking at the source code of the rendered page it does not look like there is any pre-caching being done.

Is there already an existing MODx resource that will do pre-cache rollover images ONLOAD? I do have a method that I have been using, but it isn’t very elegant and thought I would just ask y’all in case I’ve evidently missed out; no need to reinvent the wheel, y’know?

Thank you for any insight!