ImageLayers don't show up unless width and height are explicitly set

/*
This is a UI file (.ui.qml) that is intended to be edited in Qt Design Studio only.
It is supposed to be strictly declarative and only uses a subset of QML. If you edit
this file manually, you might introduce QML code that is not supported by Qt Design Studio.
Check out https://doc.qt.io/qtcreator/creator-quick-ui-forms.html for details on .ui.qml files.
*/

import QtQuick
import Constants

import QtQuickUltralite.Layers 2.0

ApplicationScreens {
    Screen {
        id: screen

        width: 800
        height: 480


        ItemLayer {
            z: 1
            width: 200
            height: 200
            
            Rectangle {
                id: root
                width: 400
                height: 200
                color: "red"
            }
        }
        
        ImageLayer {
            id: reineLofotenIslands
            z: 2
            source: "images/reine-lofoten-islands.jpg"
        }
    }
}