QImage declaration and intitialization?

If I declare a pointer to a QImage I can do this:

Code:

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QImage *myImage;
 
	//and later..
 
	myImage = new QImage(800,800,QImage::Format_ARGB32)

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And if I declare a QImage with the default constructor, it will give me a null QImage and I can do this:

Code:

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QImage myImage;
	//and later
	myImage.load(file);

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Is there any way to declare a QImage and later set it up as 800,800,QImage::Format_ARGB32 ?

This seems to work but it seems conflated:

Code:

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QImage myImage;
    QImage *temp = new QImage(800,800,QImage::Format_ARGB32);
    myImage = *temp;

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There is no QImage function to do this? Also, lets say myImage was not a null QImage, but an actual image in a class . Assigning a new image to it, does that create a memory leak or does QImage take care of that? I come from Java and the system takes care of all orphaned objects.