1. An apparatus for detecting an image converted from a first resolution to a second resolution higher than the first resolution, the apparatus comprising: a texture area determiner which divides a received second resolution image into areas having a pre-set size and which determines a texture area using frequency characteristic information of an area; a metric calculator which calculates a metric indicating an energy ratio in a frequency band from area characteristic information in the texture area; and an image determiner which determines by comparing the metric and a threshold whether the received second resolution image is a second resolution image converted from a first resolution image.