Update description.txt

Author: mobergmann

description.txt

@@ -2,7 +2,7 @@
 A Stellaris mod, which adds more flags to the game.
 This mod is Achievement compatible.
 
-[url=https://github.com/mobergmann/more-flags-mod][img]https://i.imgur.com/D7IfV4Q.jpeg[/img]
+[url=https://github.com/mobergmann/more-flags-mod][img]https://raw.githubusercontent.com/mobergmann/more-flags-mod/98e9224ab70565aca261a1c72f8093095cf726db/banner.jpg[/img]
 
 
 [h2]Have a flag suggestion?[/h2]