qr code sites?

Trovepix is the best choice imo. Fairly cheap and the photos get saved straight to your Google Drive so you don't have to back them up later, or rush to download them.

Founder of photogala.net here so I'm biased, but this is literally what we do!

Guests scan a QR code at the reception, it opens on their phone, and they can upload photos and videos to a shared gallery. No app to download, no sign up, just scan and go. We also added gamification like photo challenges and fun prompts which honestly makes a huge difference because otherwise a lot of guests scan it, look around, and never actually upload anything.

You can print the QR on table cards, place cards, or even a sign at the entrance. After the wedding you have all the photos in one place and can print your favorites into an album in whatever size you want.