QML Image fill from Icon resource

[Andy314]

Hello,
in the widget area its is easy to work with icons but how to do in QML.
This is my code.

            Image
            {
                id: leftimage
                 source: "qrc:///images/OK.ico"
                width: 16
                height: 16
                fillMode: Image.Stretch
                   //fillMode: Image.PreserveAspectFit
            }

I have a icon file with different sizes in it 16x16 24x24 ...... 48x48.
It seem that the Image takes the large size and and scales to it.
How can I resize such an Image, or better pick the optimal icon image for a specific fixed size (as the QPushButton performes it) ?
Explicit setting of with and height did not work - the Image has alway a large size