Blurry QMainWindow's icon (under Linux)

[cidadao]

Hello,

Im setting the main window's icon using setWindowIcon() and a 48x48 PNG image.
However, no matter the icon's size I use (I tried up to 256x256) I always get a blurry icon showing up on my distro's dock. Im using elementaryOS. Please see the following screenshot:

!http://s2.postimg.org/yvdn3hr3t/blurry_icon.png()!

Why this happens and how can I solve it?

Thanks

[clochydd]

Did you add the .png via resource file .qrc?
You should see possible versions like normal, active, selected in designer (windowIcon).