1. An audio output apparatus comprising: a speaker configured to output audio; a display configured to display an output image; and a processor configured to control the speaker to output music content as the audio, determine, based on meta data and external environment information, an image category corresponding to the music content among presorted image categories, determine at least one image corresponding to the determined image category as a background image, and control the display to display the determined at least one image as the output image, wherein the presorted image categories are categorized based on a corresponding genre of the music content and each of the presorted image categories comprise sub-categories based on corresponding external environment information.