Today's update also allows you to change the settings on your Android device so that video won't automatically start to play when you scroll to one. Instagram users might not realize that videos are preloaded so that they start quickly. But alas, this could cause you to use more data. If you go to your profile and tap on Preload, you can select from Always or Only on Wi-Fi. If you select the latter, the preloading will occur only if you are on a Wi-Fi network, saving you from using your precious data. If you do select the Wi-Fi only option, your Instagram videos might take longer than usual to start playing. For most, it might be worth waiting a little longer to see an Instagram video instead of consuming data to see it play instantly.
Both new features have already been available on iOS devices thanks to an earlier update.
source: Instagram (1), (2) via Engadget