Cycles: Use half storage for 16bit files (e.g. 16bit pngs) as well.

Note: This only works for textures loaded from disk via OIIO, not packed textures. That's still a ToDo.

intern/cycles/render/image.cpp

@@ -176,7 +176,9 @@ ImageManager::ImageDataType ImageManager::get_image_metadata(const string& filen
 			}
 
 			/* check if it's half float */
-			if(spec.format == TypeDesc::HALF)
+			if(spec.format == TypeDesc::HALF ||
+			   spec.format == TypeDesc::USHORT ||
+			   spec.format == TypeDesc::SHORT)
 				is_half = true;
 
 			channels = spec.nchannels;