Final answer:
Peripheral vision is more effective at night because it relies on rods, which are more sensitive to low light and are predominant in the edges of the retina, as opposed to the cone-rich fovea which is better for sharp central vision in well-lit conditions.
Step-by-step explanation:
It is easier to see images at night using peripheral vision rather than central vision due to the distribution and function of rods and cones within the retina. The fovea is the region at the center back of the eye responsible for sharp central vision and contains a high density of cones; however, it is not very active in low light conditions. The peripheral retina contains more rods which are significantly more sensitive to light and better suited for night vision, hence making peripheral vision more effective in the dark.
Rods are responsible for peripheral vision and operate better in low light. They also do not provide color information, which is why in very dark environments, we only discern grey scales. The transition from a well-lit environment to a darker one shifts vision responsibility from cones to rods, and this adaptation allows us to see better at night using our peripheral vision.