When is a gallery page an improvement in the user experience?

I'm looking for some ideas from other designers / developers / UX engineers about when a gallery of images is useful and has a positive impact on the user experience, not just a neutral experience.

In my mind and from my own experience, if the image gallery is not affirmatively With an impact on the user experience, it is an unnecessary element to include in a website.

There are several people in me event planning company (no e-commerce) that have requested a gallery page for each event. They are not sure what they want, but they want potential users to "get an idea" of the events.

I do not think that a gallery page is an effective sales tool. It is passive, and often does not use images of real event, since these images are added more frequently to an event page before the event takes place.

My job as an UX Engineer is to help Users "become familiar" with the event, as they experience the entire website, not just one page.