There are no questions asked when adding a photo other than selecting from the gallery what type of photo it is; entire plant, bloom, etc. It's exactly the same as adding a photo to a post like you did here.
Tuberose (Agave amica),
Click on the linked entry above, on the left side is the 'Upload a Photo' option.
Sounds like you were trying to 'Add a Plant', that's not the same as adding a photo. That's to add a new plant that is missing from the database. But you've added photos before so not sure.
Will try that later. I was trying to add a plant. Sorry. 
