Name: Evan Pioneer Valley south, MA, USA (Zone 6a)
The way to move a photo is to open it, scroll to the bottom of the page and select ยป Move this image to another plant. I've moved the photo to Christmas Cactus (Schlumbergera truncata)
Merging two entries moves all photos, comments, ... from one entry to another and deletes the newer entry. I've declined the merge request.