Country flag images (one PNG per ISO 3166-1 alpha-2 code, 42x30).

These are the game client's own flag textures (typebeat.Game.Resources, Textures/Flags, forked
from ppy/osu-resources), downscaled for the website so the site and the game show the same flags.
Those textures were generated by ppy's osu_flags.sh from:

  Twemoji 14.0.2, Copyright 2020 Twitter, Inc and other contributors
      https://github.com/jdecked/twemoji

Licensed under the Creative Commons Attribution 4.0 International licence (CC-BY 4.0):
https://creativecommons.org/licenses/by/4.0/

Changes: rasterised, saturated and lightened, and padded to a common aspect ratio by
osu_flags.sh; resized from 150x108 to 42x30 for the website.