@dansup @grishka For the audio, I'd go with the imgur approach: Muted by default (per "browsing session"), but as soon as you enable audio on any video, every video you scroll into view starts with audio. Until you mute any video again.
But yeah, a general bandwidth saving option (no preloading, load low-res thumbnails only, load hi-res images/video only once one clicks through) would be nice. There are still people trävelling with Deutsche Bahn. ;)
Dave, Instagram does this and it's absolutely horrible. You enable audio once, then you spend a minute scrolling through photos, then you end up seeing a video and it startles you.
Deutsche Bahn taught me the German word Verspätung.