Documentation at https://doc.qt.io/qt-5/scalability.html states that:

"On macOS and iOS, you can provide alternative resources with double the size and the @2x identifier for icons and images and place them in the resource file. On Retina displays, the @2x versions are used automatically."

Documentation recommends doing this:

Image {
    source: {
        if (Screen.PixelDensity < 40)
        "image_low_dpi.png"
        else if (Screen.PixelDensity > 300)
        "image_high_dpi.png"
        else
        "image.png"
        }
    }
}

I tested on my Android devices and @2x images do get loaded using qml Image. I think it's important to clearly state what the supported and recommended way of loading multiresolution images really is.