The system runs multiple scans so the icon may change (especially in the first few hours after upload). We made improvements to this experience and we’ll continue to work on it, here’s more info on that update: https://goo.gl/FkFSHC
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more