You can disable the auto-download. Settings > Data and storage > Media auto-download, you can choose what to auto download for mobile data/wifi/roaming.
hmm. I find the auto-download setting in the mobile app but not on desktop (mac). anyone know?
it looks like it can’t be disabled for view-once media (or at least, that’s what the settings screen says)
Thank you! That's what I get for quick scrolling through the settings. I for sure thought it would have been under Privacy (for this concern), but that makes sense too.