How is taking a picture creepy?
I think it's the context that makes it weird for me, like everything to do with Photo Kano. I know you've asked before why so many people find the idea of the show creepy and I've wanted to try and explain from my perspective for a few days, so here goes -
warning this post is going to be TL;DR
First off, with the GIF in particular, the girl in the picture is frozen in place, waiting for the snap to happen - she's basically "on hold" for the audience, no longer a character but a prop. As is often the case with CG anime, she also looks a bit weird and fake - she looks like "there's nothing going on behind the eyes", soulless and a bit dead.
The main issue for me, though, is the whole concept of Photo Kano.
Most people like taking photos, obviously. We capture memories of people and places we find interesting. Sometimes it's a bit artificial, but photography gives us memories of things we're close to emotionally.
Of course, people take sexy or private photos of their partners all the time. Sometimes that even happens in films. Where Photo Kano's premise differs is in what the context of that photography implies.
When you have someone taking a photograph in a film or a TV show, it's either revealing something about the photographer themself or their subject. That's what's interesting about it - whether it's something sexual or otherwise. It's part of the "journey" towards understanding a character or a scene. In Photo Kano, it's not the journey - it's the goal. The main character joins a club with a focus on erotic photography so he can take sexy photos of girls. That's it - that's the reason the show exists, for stills of upskirt and cleavage shots of a bunch of different girls.
Of course there are huge numbers of anime that are thinly veiled excuses for fanservice, that's nothing new. But the other issue about photography is the "distance" it puts between the photographer and the thing being photographed. People talk about "the subject" of a photograph - it turns people into abstract objects, not even people at all. The replication of the camera viewfinder effect in the show adds yet another layer of abstraction on to what's happening, as the viewpoint goes:
audience -> TV screen -> viewfinder -> girl
Look, I realise I'm overthinking this, and very few other people are going to feel as creeped out by Photo Kano as I am. If the girls' personalities are appealing and the fanservice shots are sexy then I'm sure there are loads of people who will enjoy it. But I just wanted to try and explain what exactly it was that makes this show a bit more uncomfortable than most other bishoujo adaptations.