Set image for qml camera from c++

[neda]

Hi,
I convert image of camera to base64 string.

QFile fileImg(url of image); // == camera.imageCapture.capturedImagePath
        fileImg.open(QIODevice::ReadOnly);
        QByteArray imageData = fileImg.readAll();
        QByteArray imageData_Base64 = imageData.toBase64();
        xmlWriter.writeAttribute("image",imageData_Base64);

QFile fileImg(url of image); // == camera.imageCapture.capturedImagePath
        fileImg.open(QIODevice::ReadOnly);
        QByteArray imageData = fileImg.readAll();
        QByteArray imageData_Base64 = imageData.toBase64();
        xmlWriter.writeAttribute("image",imageData_Base64);

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I have a string like this:
/9j/4AAQSkZJRgABAQEAYABgAAD/2wBDAA ......

Now I want show above string as image in qml camera.

Please guide me.