This migth evolve into examples of OpenRaster. Structure is more imporant than exact XML syntax.

00-image.xml
<image>
    <layers>
      <layer src='data/romedalen.jpg'/>
    </layers>
</image>

01-layers.xml
<image>
    <layers>
        <layer src='data/OpenRaster.png'
               x='10'
               y='40'/>
        <layer src='data/OpenRaster.png'
               x='72'
               y='8'/>
      <layer src='data/romedalen.jpg'/>
    </layers>
</image>

02-layer-opacity.xml
<image>
    <layers>
      <layer src='data/OpenRaster.png'
             x='72'
             y='8'
             opacity='0.7'/>
      <layer src='data/romedalen.jpg'/>
    </layers>
</image>

03-layer-group.xml
<image>
    <layers>
      <layer x='50' y='10'>
        <layer src='data/OpenRaster.png'
               x='0'
               y='0'/>
        <layer src='data/OpenRaster.png'
               x='20'
               y='20'/>
      </layer>
      <layer src='data/romedalen.jpg'/>
    </layers>
</image>

04-non-destructive-adjustments.xml
<image>
    <layers>
        <brightness-contrast contrast='1.4'/>
        <unsharp-mask radius='0.8'/>
        <layer src='data/romedalen.jpg'/>
    </layers>
</image>

05-misc.xml
<image>
    <layers>
        <layer x='50' y='5'>
            <dropshadow radius='10' x='10' y='10' opacity='0.5'/>
            <layer src='data/OpenRaster.png'/>
        </layer>
        <layer y='50'>
            <invert/>
            <layer src='data/OpenRaster.png'/>
        </layer>
        <brightness-contrast brightness='0.0' contrast='0.8'/>
        <scale x='1.0' y='2.0'/>
        <layer src='data/romedalen.jpg'/>
    </layers>
</image>