diff --git a/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java b/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
index 1601207ed..c57bfc269 100644
--- a/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
+++ b/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
@@ -74,7 +74,7 @@ public class ThumbnailManager {
 
     protected String imageExtention = "png";
 
-    protected int splitSize = 2;
+    protected int splitSize = 3;
 
     protected int thumbnailTaskQueueSize = 10000;