1. An image outputting device, comprising: a camera configured to obtain a viewer's image; a display configured to reproduce content; and a controller configured to: set up a specific condition of a dual-recording function; reproduce the content and display the content on a whole screen of the display; perform the dual-recording function for recording both the viewer's image obtained by the camera and the content being reproduced, and further display the viewer's image on a partial area overlapped with the content when the specific condition of the dual-recording function is satisfied; and generate a dual-recording image by performing the dual-recording function and store the dual-recording image, wherein the specific condition is determined by at least one of a highlight period among additional information of the content, a specific word among caption information of the content, a facial expression of the viewer and a predetermined gesture.