How to only show image without terrain?

Hello, may I ask if it is possible to only create images without creating terrain in cesium for real? My understanding is that Cesium3DFileset is used for terrain types, and the CesiumTileMapServiceRasterOverlay is used for base image, so it cannot only display images. Is my understanding correct? Thank you for your answer

It doesn’t really make any sense to draw images without terrain. What would you draw them on?

But yes, your understanding is correct: none of the CesiumRasterOverlay components will do anything at all without a corresponding Cesium3DTileset.