Examples: Fix compression artifacts of normal map.

examples/webgl_materials_channels.html

@@ -120,7 +120,7 @@
 				// textures
 
 				var textureLoader = new THREE.TextureLoader();
-				var normalMap = textureLoader.load( "models/obj/ninja/normal.jpg" );
+				var normalMap = textureLoader.load( "models/obj/ninja/normal.png" );
 				var aoMap = textureLoader.load( "models/obj/ninja/ao.jpg" );
 				var displacementMap = textureLoader.load( "models/obj/ninja/displacement.jpg" );
 

examples/webgl_materials_displacementmap.html

@@ -160,7 +160,7 @@
 				// textures
 
 				var textureLoader = new THREE.TextureLoader();
-				var normalMap = textureLoader.load( "models/obj/ninja/normal.jpg" );
+				var normalMap = textureLoader.load( "models/obj/ninja/normal.png" );
 				var aoMap = textureLoader.load( "models/obj/ninja/ao.jpg" );
 				var displacementMap = textureLoader.load( "models/obj/ninja/displacement.jpg" );