The default settings for mobile was so weird. Auto play videos, and "non-HD" photo and video uploads. I reversed them as I prefer to conserve bandwidth used for my stuff by not playing random clips...
"Non-HD" photos and videos on Facebook are compressed to hell and back... Must be JPEG at something like quality 60%. There's been recommendations to just upload at a high resolution, which works fairly well when viewed on HiDPI displays as the resolution hides the artifacts, but still terrible otherwise. IIRC they had a trial with WebP but abandoned it? It's too bad we don't have good low bandwidth options there, because of course I can see their side of it too. Should honestly have been a problem solved eons ago by now.
"Non-HD" photos and videos on Facebook are compressed to hell and back... Must be JPEG at something like quality 60%. There's been recommendations to just upload at a high resolution, which works fairly well when viewed on HiDPI displays as the resolution hides the artifacts, but still terrible otherwise. IIRC they had a trial with WebP but abandoned it? It's too bad we don't have good low bandwidth options there, because of course I can see their side of it too. Should honestly have been a problem solved eons ago by now.