pegelli's observation of the scaling seems to be correct, which suggests that PeterA has a browser window that is full screen, or close. On my 4.5K iMac, with a window that is full height but about 65% of screen width, the whole of lookbook's image shows comfortably. If I stretch the window to full width, it becomes slightly too tall. I think that the scaling is to the width of the browser window, as pegelli says. When a post contains a high resolution image in portrait format, I have to scroll to see all parts of it. Also, on a somewhat mediocre internet connection, like mine, these very high resolution images take some time to load (and scale). Given that the vertical resolution of 5K is ~2880 pixels, linking to extremely high resolution images seems a bit excessive, in my opinion.