Comment 29 for bug 137764

(In reply to comment #20)
> So won't this approach mean that any repaint after the image has timed out has
> to redecode the image?

I think this is preferable to Firefox filling up all available physical memory
- swapping to disk hurts performance of the whole operating system more, than
having to redecode images (although I won't say it can't be annoying).

(In reply to comment #19)
> Could this involve some sort of formula that
> looked at what percentage of RAM is available and set the time accordingly?

There are cache memory limits (that are derived from total RAM available) that
should be used in such calculations, not really the physical ram size. See Bug
213391 (for those interested - theres also a testcase that makes FF's memory
usage jump really high almost instantly).