Entirely disagree. Unless the scale of the object is unusual or exceptional to the extent that it is necessary for the illustration (for example if this was an image of the a world record sunflower) then it is inappropriate to include a scale bar. It's all the more inappropriate where the scale is not precise but a mere approximation. At any rate, I've updated the caption --Fir000206:45, 28 August 2009 (UTC)