Option 1 : is an interesting idea, but I agree with the fact that you can saturate quickly the quota of storage allowed.
Option 2 : Personally I don't see any interest in this option.
Might it exists a non destructive compression for raw or fits files. that might give a better interest to option 1 ?
One idea, very often the digitization of the light signal is done on 10, 12 or 14 bits so there is 6 to 2 leadings bits usefulness. Why not trying to pack the datas ?
It took a look on the fpack utility. It is very effricient on fits files. Reducing the size to half "in a trice" with the Hcompress algorithm on the images I tested.
Regarding use case for cloud storage: thought it could be great for group projects, where users like us agree on a target (e.g. a certain galaxy) and upload all images they have taken of that target. Maybe, leveraging also on all the metadata related to the file, all such images can be stakked. So we could efficiently generate images with long exposure times. I am not sure if technically that could work, and maybe it is not a new idea, so apologies in a advance if this is a dumb proposal...