[gimp] libgimp: update docs of gimp_image_metadata_save_prepare()

[Michael Natterer <mitch src gnome org>]

commit 16e01dc193622e9127f2238e40a1b11563e517df
Author: Michael Natterer <mitch gimp org>
Date:   Thu Jun 5 15:50:05 2014 +0200

    libgimp: update docs of gimp_image_metadata_save_prepare()

 libgimp/gimpmetadata.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/libgimp/gimpmetadata.c b/libgimp/gimpmetadata.c
index 3cb8e59..bea9e6d 100644
--- a/libgimp/gimpmetadata.c
+++ b/libgimp/gimpmetadata.c
@@ -180,12 +180,19 @@ gimp_image_metadata_load_finish (gint32                 image_ID,
 
 /**
  * gimp_image_metadata_save_prepare:
- * @image_ID:  The image
- * @mime_type: The saved file's mime-type
+ * @image_ID:        The image
+ * @mime_type:       The saved file's mime-type
+ * @suggested_flags: Suggested default values for the @flags passed to
+ *                   gimp_image_metadata_save_finish()
  *
  * Gets the image metadata for saving it using
  * gimp_image_metadata_save_finish().
  *
+ * The @suggested_flags are determined from what kind of metadata
+ * (Exif, XMP, ...) is actually present in the image. The suggested
+ * value for GIMP_METADATA_SAVE_THUMBNAIL is determined by whether
+ * there was a thumbnail in the previously imported image.
+ *
  * Returns: The image's metadata, prepared for saving.
  *
  * Since: GIMP 2.10