diff --git a/ChangeLog b/ChangeLog
index 38dc7f85..3dcb60ba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,7 @@
 - more tests
 - renamed VIPS_FOREIGN_DZ_DEPTH_1 as VIPS_FOREIGN_DZ_DEPTH_ONE etc. to help
   bindings
+- vipsthumbnail will return an error code if one or more conversions failed
 
 24/12/14 started 7.42.1
 - add gobject-2.0 to Requires: in vips and vips-cpp .pc files
diff --git a/man/vipsthumbnail.1 b/man/vipsthumbnail.1
index d589ad0b..0e488516 100644
--- a/man/vipsthumbnail.1
+++ b/man/vipsthumbnail.1
@@ -120,6 +120,8 @@ normally runs silently, except for warning and error messages. This option
 makes it print a list of the operations it performs on each image.
 
 .SH RETURN VALUE
-returns 0 on success and non-zero on error.
+returns 0 on success and non-zero on error. Error can mean one or more
+conversions failed.
+
 .SH SEE ALSO
 vipsheader(1)
diff --git a/tools/vipsthumbnail.c b/tools/vipsthumbnail.c
index 690d9c33..1104ed47 100644
--- a/tools/vipsthumbnail.c
+++ b/tools/vipsthumbnail.c
@@ -61,6 +61,8 @@
  * 12/9/14
  * 	- try with embedded profile first, if that fails retry with fallback
  * 	  profile
+ * 13/1/15
+ * 	- exit with an error code if one or more conversions failed
  */
 
 #ifdef HAVE_CONFIG_H
@@ -730,6 +732,7 @@ main( int argc, char **argv )
 	GOptionGroup *main_group;
 	GError *error = NULL;
 	int i;
+	int result;
 
 	if( VIPS_INIT( argv[0] ) )
 	        vips_error_exit( "unable to start VIPS" );
@@ -770,6 +773,8 @@ main( int argc, char **argv )
 		thumbnail_height = thumbnail_width;
 	}
 
+	result = 0;
+
 	for( i = 1; i < argc; i++ ) {
 		/* Hang resources for processing this thumbnail off @process.
 		 */
@@ -780,6 +785,11 @@ main( int argc, char **argv )
 				argv[0], argv[i] );
 			fprintf( stderr, "%s", vips_error_buffer() );
 			vips_error_clear();
+
+			/* We had a conversion failure: return an error code
+			 * when we finally exit.
+			 */
+			result = -1;
 		}
 
 		g_object_unref( process );
@@ -787,5 +797,5 @@ main( int argc, char **argv )
 
 	vips_shutdown();
 
-	return( 0 );
+	return( result );
 }