Optimized thumbnail generation: If the image was not edited yet anyway, only the (fast) raw internal preview image is taken. So if you just downloaded the many pictures from the camera, your machine will not busy generating thumbnails.

rtgui/thumbnail.h

@@ -85,6 +85,7 @@ class Thumbnail {
         void              loadProcParams ();
 
 		bool              isQuick() { return quick_; }
+		bool              isPParamsValid() { return pparamsValid; }
         bool              isRecentlySaved ();
         void              imageDeveloped ();
         void              imageEnqueued ();