How to edit icon for Korean input source?

I use the English and Korean input sources on my Macbook.

For some reason or other, the English one has a U.S. flag as its icon, but the Korean one has a completely different icon — the letter "⬜" instead of the Korean flag. This really bugs me.

I've tried using the program Ukelele to make my own input source with the Korean flag as its icon, but apparently Ukelele doesn't support the Korean input method.

So is there a way to edit a preexisting input source? I'm looking to change the icon of the default Korean input source on the OS X.

EDIT: Apparently StackExchange thinks all Koreans must be spammers. The letter "⬜" (which has been replaced) looks like this: https://ko.wikipedia.org/wiki/%ED%95%9C

Solution 1:

Go to System/Library/Input Methods/KoreanIM.app and view its Package Contents/Contents/Resources. There you will see .pngs for the various Hangul IM's. Try replacing the relevant one of those and see if that does the trick.