code: def drawcircle(self, x, y, r = 10, colour = None, label = None):
          
          
          self.checkforpilimage()
          colour = self.defaultcolour(colour)
          self.changecolourmode(colour)
          self.makedraw()
          
          (pilx, pily) = self.pilcoords((x,y))
          pilr = self.pilscale(r)
          
          self.draw.ellipse([(pilx-pilr+1, pily-pilr+1), (pilx+pilr+1, pily+pilr+1)], outline = colour)
          
          if label != None:
              # The we write it :
              self.loadlabelfont()
              textwidth = self.draw.textsize(label, font = self.labelfont)[0]
              self.draw.text((pilx - float(textwidth)/2.0 + 2, pily + pilr + 4), label, fill = colour, font = self.labelfont)
docs: Draws a circle centered on (x, y) with radius r. All these are in the coordinates of your initial image !
          You give these x and y in the usual ds9 pixels, (0,0) is bottom left.
          I will convert this into the right PIL coordiates.