diff --git a/doc/Makefile.am b/doc/Makefile.am
index b8a68a3..fcd2db0 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,6 +1,6 @@
 if DOCS
 dist_man1_MANS = mg.1
-dist_doc_DATA  = tutorial .mg mg.png
+dist_doc_DATA  = tutorial .mg mg.png mg-thumb.png
 endif
 EXTRA_DIST     = AUTHORS