Small fix that closes #1301:

It turns out that we can keep the inserting order as before and fix this by just supplying the original layer's zIndex.
I go with layer.getZIndex() right away as it a) exists on all types of Layers in OL and b) always returns a Number according to the API.

new-client/src/plugins/Print/PrintModel.js

@@ -603,6 +603,7 @@ export default class PrintModel {
       const imageLayer = new ImageLayer({
         opacity: layerOpacity,
         source: imageSource,
+        zIndex: layer.getZIndex(),
       });
       // Finally we add the new layer to the map... First we have to check where
       // the original layer was placed (so that it keeps its draw-order).