Using OpenCV module, you can make use of cv2.circle().
image = cv.circle(image, centerOfCircle, radius, color, thickness)
For plotting a single point on image, you can keep radius as 0 and for filled circle, you can give thickness as negative number
image = cv2.circle(image, (x,y), radius=0, color=(0, 0, 255), thickness=-1)
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