diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..a1c4eb9
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "demo"]
+	path = demo
+	url = https://github.com/vipqualitypost/string-demo-images
diff --git a/demo b/demo
new file mode 160000
index 0000000..64fedcd
--- /dev/null
+++ b/demo
@@ -0,0 +1 @@
+Subproject commit 64fedcd3c93fa87802e9bf4540cedad8c11d5909