Margaret, yes, it's already in place. If you go to the main page for a particular plant you can thumbs up the plant itself. Click on this:
Cat's Ear (Hypochaeris radicata)
in the upper right corner near the photo is a thumbs up which will signify a thumbs up for that plant. You will notice that the photos (thumbnails) below the data have thumbs up you can click on to signify your compliment for that particular photo. See, in the thumbnails the photo in the upper right on the is repeated below.
