Travel Tracker - Countdown uses a 16:9 aspect ratio. Prepping your pictures in this aspect ratio will give best results when they are displayed.
Travel Tracker - Countdown has a public GitHub repo for issues.
You may need to re-add your trips to get them to sync to iCloud. If that still doesn't work, delete the app and reinstall.
Travel Tracker - Countdown is free as in beer for everyone to enjoy! If you do want to give back, buy me a coffee!.
Contact support via email