If you know the photos are going to be used exclusively for ig, I would ensure they're all exported in a way that minimizes the cropping IG will do. Also you could just send all photos in portrait mode to this specific client to have a little more control over how they turn out. It's annoying but most people who aren't photogs don't realize this so I try to mitigate this by giving them fewer options after editing.
If you know the photos are going to be used exclusively for ig, I would ensure they're all exported in a way that minimizes the cropping IG will do. Also you could just send all photos in portrait mode to this specific client to have a little more control over how they turn out. It's annoying but most people who aren't photogs don't realize this so I try to mitigate this by giving them fewer options after editing.