[tracker1]

That CDN isn't free all the content and traffic overhead has costs, CDN charges you for each request, and every byte sent. On a small (under a million users a day) application it may not be that much... but even ten of millions of users a day, it costs a LOT

Hell, why do you think google invested so much time into image compression tech to save a few bytes here and there.

[Brakenshire]

I doubt it’s much, the whole OSM infrastructure used to be handled as a favour by one of the London universities. I doubt DDG Maps is operating at significantly higher scale, especially once you take into account they just have to serve static data.