What is the difference between QImage and QPixmap?

Question

I do not understand what is the difference between QImage and QPixmap, they seem to offer the same functionality. When should I use a QImage and when should I use a QPixmap?

Answer 1

One important difference is that you cannot create or manipulate a QPixmap on anything but the main GUI thread. You can, however, create and manipulate QImage instances on background threads and then convert them after passing them back to the GUI thread.