#include <QImage>
#include <QDebug>

int main(int argc, char **argv) {
    unsigned char *img = new unsigned char[3];
    img[0] = 0;
    img[1] = 0;
    img[2] = 0;

    // Create two images
    QImage *qimg1 = new QImage(img, 1, 1, QImage::Format_RGB888);
    QImage *qimg2 = new QImage(5, 5,  QImage::Format_RGB888);
    
    // Copy image 1 -> image 2
    *qimg2 = *qimg1;        // This could also be a call over a queued connection, copy constructor has same issue.

    // Destroy image 1 and the data buffer
    delete qimg1;
    delete[] img;   // This is valid according to documentation, because the QImage is destroyed

    // now access the data of the "copied" image
    unsigned char p0 = qimg2->scanLine(0)[0];       // Access to invalid memory, because now the copy is made from the invalid location
    qDebug() << static_cast<int>(p0);               // This line is here to print the contents of the invalid memory location if the program does not terminate 
                                                    // on the previous line.
                                                    // If you have a compiler that changes the memory contents when calling "delete[] img;" then 
                                                    // this will not return 0, which proves that this location is invalid. 
                                                    // Apparently Visual Studio 2008 SP1 with debug configuration and attached debugger changes the memory on delete
                                                    // so you will get 238 instead of 0.
    return 0;
}