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?

Thanks

Cathy