This may sound like a strange request, but when I first added my M3U file the channels and guide populated with some very nice (I believe default) Channel Icon with the Flag of the country it was from behind it. I actually kind of liked it because it allowed me to know what country the Channel was from (A&E with USA vs A&E with Spanish Flag for example)
What happened though is after EPG refreshed after 24 hours, then the icons were replaced by just the channel icons, the png that were bigger, perhaps more poppy and they look nice, but I would love to see if there is a way to retain the Flag Backed Ones somehow, or to have the Flag in the background of the newer ones.
I can provide screenshots if needed.