Using a custom QNetworkAccessManager in QML

The QML Image component has the capability to specify the source of the image is as a URL (using the "source" property) and QML automatically retrieving such image file from a remote location. To do so, QML uses a QNetworkAccessManager (QNAM for short) in the background, which has a lot of default values. But what if you need to set some custom values for the QNAM?