If you look at the ANN threads using images for websites and social media on pc/laptop and compare it using mobile devices, you'll notice that the size is different. The one on mobile appears to be larger and doesn't fit the screen that's why you see other images below instead of seeing them in
one line.
Maybe @bubbalex can explain this better than me as he uses images for most (if not all) of his ANN threads. Use this as example
https://www.altcoinstalks.com/index.php?topic=138053.0