Take a new photo. It can be from the same position as the first one, but because it is a new photo, it won’t be identical.
Having pictures in your phone’s gallery is proof of nothing. I can download photos from the internet and put them into any photo folder I like and call them whatever I want to.
The work required by Niantic to prove that the photo on a third-party website is yours is probably more than the work required for you to take a new photo. Since the onus is generally on the reviewer to prove their submission, it seems reasonable for you to just take a new photo.
Although there is a nice symmetry in your current photo one at a slight angle might work well since it is about the whole space. raising the camera to look down more might make it clearer that this is a place to sit and chat and the table will show up more. I would even be tempted to move the seats into an arc shape around the table to make feel more natural and less formal. YOu can always move chairs back
I know I may be new and all but I do have a whole lot of info about technology and if you use pic2map it may help to prove the location and then jimple or another exit photo data viewer to help determine if the photo is genuine or not?
Your suggestion may help prove the photo’s location and its genuineness, the topic being discussed is third-party photo issues — the same photo posted on another website in particular.