Safari 6.0.3 image problems

I'm having a problem with images looking pixelated when scaled down in Safari 6.0.3 - problem not manifesting in 6.0.2.

It's a responsive site I'm building, so scaling is essential. The images all behave as expected in other browsers.

Anyone else come across this issue or any ideas how to solve?

I've tried :
image-rendering: optimizeQuality;
but this doesn't work.

sorry, it's only running locally on MAMP just now...

actually just noticed it's doing in on Macrumors too

the Macrumors logo top left of page looks pixelated on 6.0.3 for me - but not on other browsers on the same machine, or on 6.0.2 on other machine

also, noticing this issue on other sites.

annoyingly fixed after restarting browser.

weird.