The nature of the image formed on the retina of human eye is:

Convex by nature, human eye lenses produce real and inverted images. When an object is held in front of the lens's focal point and center, however, it produces virtual and upright images. The real and inverted images that are formed on the retina are further converted into the erect images that we see with our eyes by the optic nerve's transmission of chemical impulses to the brain.