Go to the PlantFile entry where the photo is, click on the photo to enlarge it, then click on the red 'Report an Error' button in the upper right hand corner of the page, and tell us if you'd like the photo removed or if you want it moved to the correct entry. If you want it moved, please tell us (or give us a link) what that entry is.
Would it be possible to have an old picture removed when you have a better one a couple of years later? Where the plant is bigger or prettier in some way? Too much work for admins? Just curious. I'd hate to load up PFs with relatively similar pictures.