Clip/crop/cut an image

[greenvirag]

Hi everyone!

I'm just a newbie by using image with Qt, and I have some questions.
(I didn't find the answers anywhere. Maybe here..)

So, can I manipulate an image (like .png) inside my Qt program? I don't think about composition. My goal is to clip an image, but I don't know exactly, what tool I should use. Maybe QPainter or QImage or QPicture?
What tool does support to clip an image, and save the result in an other image?
(Image: no just lines -- it is not vector-graphical, it is pixel-graphical, like a pic of butterfly..)

I think the solution is easy, just I am not prudent enough.
Thank you for your answers.

Bye,
greenvirag