You actually added it as a post to the image above by mcash70, thus starting a thread in the Photos Forum.
That happens from enlarging the photo in the database entry and adding your image to the "Post a comment about this photo" box, looks exactly like this post box which has the upload image button below it.
To add image to a database entry, use the upload link in the Adding Actions section found on the entry for this plant. You can go directly to the entry by clicking on the name of the plant in the top photo.
Adding Actions:
» Upload a photo
» Upload a URL photo
» Post a comment
» Add an event report
» File a local report