By default, the Highlights Cover is the first image in the Highlight. However, you can also choose a different image for the Highlight Cover. Open the Instagram app.

Instagram highlights act as a digital scrapbook, showcasing memorable moments on profiles. Users have full control over presentation, including cover photo customization and story management ...

If you prefer dark mode, if it isn't already enabled, you'll want to activate it on the Instagram app. Follow these steps to turn on dark mode on Android: Open Instagram on your Android device.