Who can see the photos I upload?

The host and their moderators always can; everyone else depends on the event’s privacy setting and on whether you left the photo public.

Two things decide it together, and both have to allow it.

1. The event’s privacy setting, chosen by the host. A public gallery is open to anyone with the link. A protected gallery asks for the event access code first. A private gallery opens only for the host, the moderators they invited and guests who have joined the event with its access code — the link on its own shows nothing.
2. Your own “Make photo public” switch on the upload screen. Turn it off and the photo goes only to the host and their moderators, whatever the event setting says.

A photo is shown in the gallery only when it is marked public and it has passed its check and it has not been deleted. All three are required on every request, so a photo the host hides or removes stops being visible straight away, including to anyone who already had the link to the image itself.