Graphics are pixelated during moving/scaling/rotating

Moving, scaling or rotating images in QtWebKit from Qt 4.8.0 makes them pixelated. After half a second after the moving stops they switch to smooth version. It looks very bad.
It's on Windows XP using Qt 4.8.0. Steps to reproduce: scale a PNG image in img tag. Watch how it behaves after scaling.

Image example: http://wieza.iq.pl/beforeafter.png - on the left is how the image looks while it's moving or scaling, on the right how it looks 0.5 seconds after stoping.

I make my QtWebView like that:

this->ui->webView->setRenderHint(QPainter::Antialiasing, true);
this->ui->webView->setRenderHint(QPainter::SmoothPixmapTransform, true);

Maybe it's related to some optimisations?
Maybe related: http://code.google.com/p/chromium/issues/detail?id=55495

I reported it also here:https://bugs.webkit.org/show_bug.cgi?id=74600