fix missing img

docs/modules/tutorials/pages/beginner/hello_terrain.adoc

@@ -214,7 +214,7 @@ Now you start painting the texture:
 ..  Paint blue lines where you want roads to criss-cross the landscape.
 .  The end result should look similar to this: +
 image:tutorials:beginner/mountains512.png[mountains512.png,64,64] ⇒
- image:jme3/beginner/alphamap.png[alphamap.png,64,64]
+image:jme3/beginner/alphamap.png[alphamap.png,64,64]
 
 
 === Looking at the Texturing Code