Keep work and personal sharing expectations clear
For company events, explain whether photos are only for attendees or might later be considered for other uses. An event upload is not by itself permission to use a picture in a public campaign.
Ask participants to avoid confidential screens, badges, documents and anyone who does not want to appear. Choose approval when a review before gallery visibility is useful.
Make room for people who would rather watch
Photo sharing can stay optional. A participant can enjoy the event without having to take a selfie or complete a board.
Provide a direct link as well as a QR code, and test joining and uploading on a phone before the event. A trusted co-organizer can help explain the process at the venue.