When the object distance is less than the focal length, it becomes a vertical magnified virtual image. The closer the object is to the mirror, the smaller the image is. When the object distance is equal to a focal length, no image is formed, and when the object distance is between one and two focal lengths, it becomes an inverted magnified real image. The farther the object is from the mirror, the smaller the image. When the object distance is equal to twice the focal length, it becomes an anti-reflection real image. When the object distance is greater than twice the focal length, it becomes an inverted and reduced real image. The farther the object is from the mirror, the smaller the image. The real image is on the same side as the object, and the virtual image is on the opposite side.

So concave mirror can image the flame of a candle on the screen.