I think it would be really helpful to be able to zoom in when looking at/selecting a bunch of images on the grid view. I sometimes take several photos of a scene, then want to get rid of any blurry ones. Sometimes I need to zoom in to see how clear the image is. If I have, say, a group of 10 images, I’d like to be able to zoom in then decide whether to select it or not. That way, I could find the 6 that were blurry and delete them quickly.
Another way that this could work is if I could add/remove images from my selection when I was in the “viewing image with multiple thumbnails visible” mode (sorry I’m new to the app, and don’t yet know the correct words). This is the screen you get to after tapping a single image in the grid view.