diff --git a/README.md b/README.md
index 56b0c2d..317be1b 100644
--- a/README.md
+++ b/README.md
@@ -56,3 +56,5 @@ up to C++11, std::unique\_ptr is used instead.
 # Legal Stuff
 
 [This program uses FFmpeg which is licensed under the LGPL 2.1 license](https://ffmpeg.org/legal.html)
+
+[This program uses libpng which is licensed under the PNG Reference Library License Version 2](http://www.libpng.org/pub/png/src/libpng-LICENSE.txt)