[gnumeric] Don't crash when dragging an unkown image

[Jean BrÃfort <jbrefort src gnome org>]

commit a65910b3d4d9317415e019532dd6f900ad4ffeab
Author: Jean Brefort <jean brefort normalesup org>
Date:   Sat Nov 10 19:06:19 2012 +0100

    Don't crash when dragging an unkown image

 ChangeLog                |    5 +++++
 src/sheet-object-image.c |    2 +-
 2 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index efb3939..19663c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-11-10  Jean Brefort  <jean brefort normalesup org>
+
+	* src/sheet-object-image.c (gnm_soi_get_target_list): don't crash when
+	draging an unkown image.
+
 2012-11-08  Andreas J. Guelzow <aguelzow pyrshep ca>
 
 	* src/cell-draw.c (cell_draw_simplify_cb): change argument type and flag
diff --git a/src/sheet-object-image.c b/src/sheet-object-image.c
index 80f73a1..808008b 100644
--- a/src/sheet-object-image.c
+++ b/src/sheet-object-image.c
@@ -256,7 +256,7 @@ gnm_soi_get_target_list (SheetObject const *so)
 	GSList *mimes, *ptr;
 	GdkPixbuf *pixbuf = NULL;
 
-	if (soi->type == NULL)
+	if (soi->type == NULL && soi->image != NULL)
 		pixbuf = go_image_get_pixbuf (soi->image);
 	mime_str = go_image_format_to_mime (soi->type);
 	if (mime_str) {