fix links to point to tutorials image

docs/modules/ROOT/pages/jme3/advanced/terrain.adoc

@@ -82,7 +82,7 @@ We recommend to <<sdk/terrain_editor#,create and edit Splat Textures for terrain
 Here are the names of TerrainLighting.j3md's material properties:
 
 [.right.text-left]
-image::jme3/beginner/mountains512.png[A heightmap encodes the topological highs and lows of the terrain,width="128",height="128"]
+image::tutorials:beginner/mountains512.png[A heightmap encodes the topological highs and lows of the terrain,width="128",height="128"]
 
 
 *  1-3 Alpha Maps

docs/modules/ROOT/pages/jme3/terminology.adoc

@@ -139,7 +139,7 @@ There are two types:
 **  You use Height Maps to model large terrains with valleys and mountains.
 --
 [.right]
-image::jme3/beginner/mountains512.png[mountains512.png,128,128]
+image::tutorials:beginner/mountains512.png[mountains512.png,128,128]
 
 * *Height Map*
 **  A height map is a grayscale image looking similar to a terrain map used in topography. Brighter grays represent higher areas and darker grays lower areas.

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

@@ -212,7 +212,7 @@ Now you start painting the texture:
 ..  Paint the white hills green – this will be the dirt of the mountains.
 ..  Paint blue lines where you want roads to criss-cross the landscape.
 .  The end result should look similar to this: +
-image:jme3/beginner/mountains512.png[mountains512.png,64,64] ⇒
+image:tutorials:beginner/mountains512.png[mountains512.png,64,64] ⇒
  image:jme3/beginner/alphamap.png[alphamap.png,64,64]