Welcome to the community, @Nicola_Wood!
Unfortunately, none of those things are possible with Airtable’s built-in gallery (which is very flawed, in my opinion).
I highly recommend that you submit this as a feature request in the #show-and-tell:product-suggestions category, and I will chime in on your post there.
Every single one of my Airtable clients who have ever tried to use the gallery have always needed BOTH OF THESE THINGS that you requested.
Ultimately, I’ve had to switch my Airtable clients to using MiniExtensions’ gallery view instead, which is located at the link below.
The downside is that it costs an extra $40 per month, but the great news is that it does everything that you have requested, and sooooo sooooo much more.
It’s the absolute perfect gallery for Airtable, and quite honestly, it’s the gallery that Airtable SHOULD’VE built into their product but never bothered to do so.