How to draw a circle around blob objects in an image??

I have about 180 images .... I draw circle about blob objects in each image using the following code

i goes from 1 to 180

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 figure
  imshow(Or_Im{i}, [ ]); 
  hold on
  for k = 1 : numberOfBlobs{i}           % Loop through all keeper blobs.
    itsRound{i} = logicalKeepersIndexes{i}(k); % See if this blob is considered round.
    if itsRound{i}
      % Plot round blobs with a green circle.
      plot(centroidsX{i}(k), centroidsY{i}(k), 'ro', 'MarkerSize', 30, 'LineWidth', 1);
      end    
  end
  hold off

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I want to draw the circle on the 180 images and save the resulted image without using "figure", "imshow" and "plot"