The plant combo pics could be so much more valuable if they had a date and location at least. A caption box could be used to add names for those who can't use the existing box-drawing facility - and whatever other info they feel like sharing.
The original puppies are grown by now, but new ones are still suffering...! LOL!
The thread "Date, location, caption for multi-plant photos" in
Site Talk forum
I think of the combo pics as a way to connect a pic to more than 1 plant and without any connection, it seems like a pointless exercise to upload a pic as a combo. An untagged pic can only be found by scrolling through the pages of combo pics. By the next day, or sooner, it is literally lost in space without any info that could be of any use to a gardener in the future, should they happen to click "next" a hundred times.
Could connecting to a plant in the DB be separated from the action of defining where the plant is in the pic? Could one just add a list of plants that appear in the pic without trying to draw a box where they appear? If that is possible, then I do think it should be a requirement to connect the pic to at least 1 plant in the database, but not drawing the box if some devices can't utilize that part of the upload facility.