Part of #217: Fix preview image water color for River Styx

The preview image has water colouring match the currently selected palette, the valkyrie statue had to be moved.

Author: 733737

objects/rct2tt/ride/rct2tt.ride.rivrstyx/images/preview.png

@@ -46,7 +46,8 @@
         }
     },
     "images": [
-        "$RCT2:OBJDATA/RIVRSTYX.DAT[0..98]"
+	     { "path":"images/preview.png" },
+        "$RCT2:OBJDATA/RIVRSTYX.DAT[1..98]"
     ],
     "strings": {
         "name": {