Woah! That worked!

In my code the QPixmap frame is a member variable. So it is not falling out of scope. The QImage however, as a stack variable, is falling out of scope. So I guess we have to proceed from the supposition that a reference to the image was being held.

Reviewing the documentation I see that the overload:

Qt Code: 
  1. QPixmap QPixmap::fromImage(QImage &&image, Qt::ImageConversionFlags flags = Qt::AutoColor)
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says "...without copying if possible." I guess that actually applies to both overloads.

I suppose the lesson learned is to look for detach()? If I see it I need to be mindful of the possibility that there may be lingering references if I don't call it?

Anyway, thanks again. I can move forward with my project.