They don't really have enough bits here for asymmetric crypto. How many bits are they able to reliably recover from the screenshot, especially if they want to

They don't really have enough bits here for asymmetric crypto. How many bits are they able to reliably recover from the screenshot, especially if they want to survive simple downsampling? I would guess not more than 500, probably less than that given the patterns we're seeing. You can't generate a ciphertext smaller than your key size. And 500 bits is really not enough to do typical asymmetric crypto safely.