Hallo there

I have recently taken over the admin of a piwigo gallery for an organisation and am just trying to find my way around it so apologies if this is an obvious question, I haven't managed to find the answer elsewhere.

I want to be able to download fullsize versions of the photos that have been uploaded in the past and have not managed to so far. I can download photos from the front end, but these are not full size and as far as I'm aware, there should be full size photos uploaded.

Many thanks in advance for your help with this.