Get a bunch of seeds, measure them, and use that info to add a scale marker in the image with a drawing program. Or, find a reliable source that gives the seed length. Be explicit in the image description what was done to determine the scale. Sasata (talk)
Solved?. I measured some of the same seeds in the photo before adding the graphic scale. Thank you all for considering it and specially IdLoveOne for nominating the picture and notifying me the debate. ... And sorry for my bad English. Luis Fernández García