NinePatchImageSelector cannot use relative path for source

        NinePatchImage {
            width: 50
            height: 50
            source: "images/button-background.9.png"
        }

        NinePatchImage {
            width: 50
            height: 50
            source: "images/button-background"
            NinePatchImageSelector on source {
                states: [
                    {"disabled": !mouseArea.enabled},
                    {"pressed": mouseArea.pressed },
                    {"hovered": mouseArea.hoverEnabled && mouseArea.containsMouse }
                ]
            }
        }

        NinePatchImage {
            width: 50
            height: 50
            source: "qrc:/qt/qml/NinePatchImageTest/images/button-background"
            NinePatchImageSelector on source {
                id: selector
                states: [
                    {"disabled": !mouseArea.enabled},
                    {"pressed": mouseArea.pressed },
                    {"hovered": mouseArea.hoverEnabled && mouseArea.containsMouse }
                ]
            }
        }