User blog comment:Doge325/How i do make iconz?/@comment-5362365-20170605144655/@comment-31910973-20170605144855

And with GIMP too

Make sure it's transparent background and the file name is ******-icon.png

P.S. don't do "-ball on the end of the file name, like USAball-icon.png, just fo USA-icon.png