An electronic device and an image conversion method of the electronic device, the electronic device comprising: a receiving unit for receiving a first image from a source device; a decoding unit for decoding brightness information of the first image; a converting unit for converting a dynamic range of the first image on the basis of the decoded brightness information, using a mapping function; and a display unit for displaying a second image having the converted dynamic range on a display, wherein the mapping function is a curve function including a plurality of points determined on the basis of the first image, a characteristic of a change in brightness of a display of the source device, and a characteristic of brightness of a scene of the first image. The present disclosure may generate, for example, a high dynamic range (HDR) image, which is improved from a standard dynamic range (SDR) image.