Add preview image

Author: yep

README.md

@@ -2,7 +2,9 @@
 
 Easily generate custom QR-Codes.
 
-Allows for sharing (iOS) or saving (macOS) the created QR-Code. 
+Allows for sharing (iOS) or saving (macOS) the created QR-Code.
+
+![preview](https://is3-ssl.mzstatic.com/image/thumb/PurpleSource125/v4/6a/7a/2d/6a7a2db5-502f-2f4d-320c-f6e10a5fad1b/91c53e53-28b8-45fe-a30c-645b1e49a8a5_Bildschirmfoto_2021-09-13_um_08.28.25.png/1286x0w.png)
 
 ## Download