overlay a browse image (from GeoServer) on top of its footprint polygon(a primitive)?

Hi There:

I tried to display a browse image which is served from my GeoServer on top of the image’s polygon which is a primitive drawn on the map using js. The result is that the you cannot see the browse as it is underneath the polygon primitive.

I adjusted the appearance of the primitive polygon, I can see the browse. But it’s a yellowish browse because the primitive footprint polygon is yellow which is on top of the browse image. I also noticed a minor issue: my primitive polygon is a tranlucent yellow ploygon which is displayed correct on 3D map, but it is displayed as a gray polygon on 2D map. So, the broswe image in 3D map is yellowish and in 2D map is much darker than the normal one.

Is there a way we can display the browse image on top of any primitives? Looks like Cesium always draw the primitives on top of all layers provided by an imagery privider?