Update ImageUtils.html

Adding more information to the documentation

docs/api/extras/ImageUtils.html

@@ -58,7 +58,7 @@
 		<h3>.loadTexture([page:String url], [page:UVMapping mapping], [page:Function onLoad], [page:Function onError]) [page:todo]</h3>
 		<div>
 		url -- the url of the texture<br />
-		mapping -- An instance of Three.UVMapping. Describes how the image is applied to the object.<br />Use undefined or new three.UVMapping() instead of null as a default value.
+		mapping -- Can be an instance of [page:UVMapping Three.UVMapping], [page:CubeReflectionMapping THREE.CubeReflectionMapping], [page:SphericalReflectionMapping THREE.SphericalReflectionMapping] or [page:SphericalRefractionMapping THREE.SphericalRefractionMapping]. Describes how the image is applied to the object.<br />Use undefined instead of null as a default value. See mapping property of [page:Texture texture] for more details.
 		onLoad -- callback function<br />
 		onError -- callback function
 		</div>