Yeah, you are right X)

My screen is 16:9 ..
I found the option to set the widescreen-option and now it is displayed correct.
As I said, it was a stupid problem^^ Thx dennis!!

Now another question (result from the solved problem):

For rotating another image in this image, i am putting a svg-image into an additional class, setting the transform 
origin point and setting the other image as parent of this new class.
Now this image is smaller (in comparison to the circle) as it was on my host and I had to move the transformOriginPoint.

Of course, I can adjust these by Hand everytime I change the program, but it would be nice if it stays the same. 

Do you have an idea, what the problem could be? 

The Consructor looks like this:

FrontPicture::FrontPicture(QGraphicsItem *parent, int stil)
    : QGraphicsObject(parent), function(stil), design(0)
{
    renderer = new QSvgRenderer(QString(QCoreApplication::applicationDirPath() + "/picture/picture1.svg"));
    picture = new QGraphicsSvgItem(this);

    picture->setSharedRenderer(renderer);
    picture->setScale(0.227);
    //picture->setScale(0.145);                                //original setting from windows host
    //picture->setTransformOriginPoint(-16,-10);    //original setting from windows host
    picture->setTransformOriginPoint(-25,-58);

    setPicture();
}