copy image (#22741)

examples/jsm/utils/RoughnessMipmapper.js

@@ -98,6 +98,7 @@ class RoughnessMipmapper {
 			material.roughnessMap.repeat.copy( roughnessMap.repeat );
 			material.roughnessMap.center.copy( roughnessMap.center );
 			material.roughnessMap.rotation = roughnessMap.rotation;
+			material.roughnessMap.image = roughnessMap.image;
 
 			material.roughnessMap.matrixAutoUpdate = roughnessMap.matrixAutoUpdate;
 			material.roughnessMap.matrix.copy( roughnessMap.matrix );