Real Image: Those images, which can be transferred or formed on a screen, are called as real images. These images are formed by the actual intersection of reflected or refracted light rays.
Virtual Image: Those images, which can be seen only by looking into a mirror, but cannot be transferred or formed on a screen, are called as virtual images. These images are formed by the apparent intersection of the reflected or refracted light rays.
Erect Image: Those images, which lie or are formed above the principle axis, are referred to as erect images.