Ever try to roam vBulletin on a phone with a standard phone browser?
It's the biggest pain in the arse because you can't see anything and EVERYTHING needs to be zoomed constantly. My best advise would be to not post photos from a phone. In a raw phone size, they will be too large to upload to the forums anyway. If you must post images from a phone, use a hosting service for your images and link directly to them.
I'll check to see if I have an old version of Tapatalk for the forums when I get home this evening. Even then, the current Tapatalk app will likely not work with it as they have changed their app business model.
FWIW, the forum software we are using is old. In internet years, it's a relic. However, it's VERY stable, and extremely well-loved in the forum owners community. It's been around since 2009, and a large majority of vB forum users are still using vB4+ and not the more current vB5, which is a pile of garbage. Before the "upgrade" to Xenforo on the old board last year, this is the exact same system that was in place over there. It just lacks some modern social media and phone interaction features that more contemporary software systems utilize.