A display device configured to provide content, the display device comprising: a storage unit configured to store a content information database; an input unit configured to receive a user input; a controller configured to search for at least one content including a video frame associated with a search term included in the received user input in the content information database, wherein the controller is configured to perform searching for the video frame associated with the search term using the content information database including image information with respect to the video frame included in the content; and a display configured to display a list of the searched content, wherein the controller is configured to construct the content information database by: accessing content; extracting a video frame from the accessed content; checking whether or not the extracted video frame satisfies requirements of a key frame; selecting the video frame as the key frame if the video frame satisfies the requirements of the key frame; and producing image information associated with the selected video frame; characterized in that the requirements of the key frame include whether the extracted video frame corresponds to a scene change in the accessed content, wherein a rate of the scene change is calculated by comparing a current video frame with a previous video frame, wherein a video frame is selected as the key frame if the calculated rate of the scene change is 50% or more. a storage unit configured to store a content information database; an input unit configured to receive a user input; a controller configured to search for at least one content including a video frame associated with a search term included in the received user input in the content information database, wherein the controller is configured to perform searching for the video frame associated with the search term using the content information database including image information with respect to the video frame included in the content; and a display configured to display a list of the searched content, wherein the controller is configured to construct the content information database by: accessing content; extracting a video frame from the accessed content; checking whether or not the extracted video frame satisfies requirements of a key frame; selecting the video frame as the key frame if the video frame satisfies the requirements of the key frame; and producing image information associated with the selected video frame; characterized in that the requirements of the key frame include whether the extracted video frame corresponds to a scene change in the accessed content, wherein a rate of the scene change is calculated by comparing a current video frame with a previous video frame, wherein a video frame is selected as the key frame if the calculated rate of the scene change is 50% or more. accessing content; extracting a video frame from the accessed content; checking whether or not the extracted video frame satisfies requirements of a key frame; selecting the video frame as the key frame if the video frame satisfies the requirements of the key frame; and producing image information associated with the selected video frame; characterized in that the requirements of the key frame include whether the extracted video frame corresponds to a scene change in the accessed content, wherein a rate of the scene change is calculated by comparing a current video frame with a previous video frame, wherein a video frame is selected as the key frame if the calculated rate of the scene change is 50% or more.