Chrome lags with big PNG

[leemlller]

i have only 4 PNG images (2000px 1250px) each of them 300-600Kb with transparency in jParallax Firefox deal animations smoothly but in last Chrome things look laggy.
no more than 1fps
Where may be problem? image size? res? or transparency?

example image: https://dl.dropbox.com/u/2457864/04.png

[joshbtn]

I"m seeing a similar problem. My images are half the size, however they scale up so the background is always 100% of the screen, chrome seems to slow way down with that as well. Seems to be related to requestAnimationFrame, I stuck a quick fix here https://github.com/joshatjben/jparallax/blob/quickDirtyChromeLagFix/js/jquery.parallax.js . Just commented out everything but the setTimeout fallback in the requestFrame function... it's not pretty but it did what i needed it to do.