1. An image processing apparatus comprising: a ray tracer configured to perform ray tracing with respect to first rays, selected from among all rays, for photon mapping, wherein the ray-traced first rays are selected based on any two or more of a texture of a three-dimensional (3D) object associated with the photon mapping, a direction and an intensity of a lighting from a light source, and a position of the light source associated with the photon mapping; a sampling processor configured to sample a ray space using the ray-traced first rays to obtain a photon function representing a ray space; and a reconstructor configured to reconstruct the sampled ray space using the ray-traced first rays to provide a second ray to generate a pseudo photon.