Add description for callback function

Change-Id: I28490d71828f50d1010e5f121f392db6840d2e72
Signed-off-by: Minje Ahn <minje.ahn@samsung.com>

diff --git a/include/thumbnail_util_type.h b/include/thumbnail_util_type.h
index 8f78ded..b2008a3 100755 (executable)
--- a/include/thumbnail_util_type.h
+++ b/include/thumbnail_util_type.h
@@ -68,7 +68,8 @@ typedef struct thumbnail_s *thumbnail_h;
  * @ingroup CAPI_MEDIA_THUMBNAIL_UTIL_MODULE
  * @brief Called when creating the thumbnail.
  * @since_tizen @if MOBILE 2.4 @elseif WEARABLE 3.0 @endif
- * @remarks Color space of the generated thumbnail is BGRA.
+ * @remarks Color space of the generated thumbnail is BGRA. \n
+ *                  The callback is called in a separate thread(not in the main loop).
  *
  * @details This callback is called for completion of generating the thumbnail.
  *