See the comment to the issue: JDK-8147849
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    private static final BaseMultiResolutionImage IMG
            = new BaseMultiResolutionImage(new BufferedImage[]{
        generateImage(1, Color.BLACK),
        generateImage(20, Color.RED),
        generateImage(2, Color.GRAY)
    });

2. Please remove "generateImage( 2, Color.GRAY)" from the code and run again with GDK_SCALE=2. The "20x" image will be shown again. But 1x is closer to 2x than to 20x. 
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