What is the best way to share travel photos with a group?

Create one shared album and give everyone the same link or QR code. On the trip, each person uploads their phone photos into that album; afterwards, each person takes a selfie and gets only the photos they appear in.

This beats a group chat, where photos get compressed and buried, and a shared cloud folder, where nobody can find themselves in a thousand files. Everyone ends up with a complete set of their own trip photos in full resolution.