diff --git a/demo.lua b/demo.lua
new file mode 100644
index 0000000..99f0092
--- /dev/null
+++ b/demo.lua
@@ -0,0 +1,10 @@
+local cairo = require'cairo' --used to open the file
+local bitmap = require'bitmap' --used to read its content
+
+do --open image
+  local image = cairo.load_png("/home/user/cle-usb-emulateurs.png")
+  image_infos = {width = image:width(), height = image:height()}
+  image_bitmap = image:bitmap()
+end
+local getpixel, setpixel = bitmap.pixel_interface(image_bitmap)
+print(image_infos.width, image_infos.height)