Bro, full-sized vertical images just aren't going to fly. You can't have one post stealing the whole screen like that.
Not to mention abuse, like a 600x10000 image would take up _pages_ of screen. So you have to clamp the image height at some point.
People that are asking for a pref... lol it's the easiest and the worst solution. Don't let the app become a swamp of user options. We can do this without a pref.
One suggestion: have a fade-out bottom, letting the user click to expand. So, if the image is larger than a height threshold, cut off the bottom, add the fade , and let users click to reveal.

