Nope. An observation is supposed to represent a single interaction at a single moment in time.
You could post photos of different stages in different observations, and link them with observation fields, though.
[addendum: Info on observations, including “revisiting” an organism can be found at https://www.inaturalist.org/pages/help#observations1
and also here https://forum.inaturalist.org/t/adding-photos-to-an-observation-taken-another-day/7083 ]