An image display apparatus and a method thereof. The image display apparatus includes: a display; a processor; a memory including a first buffer and a second buffer; and at least one program stored in the memory and executed by the processor. The instructions included in the program cause the processor to perform graphics processing on a first image, convert an attribute of the graphics-processed first image, generate an on screen display (OSD) image and control the memory to store the OSD image in the second buffer, perform image quality processing on the first image of which the attribute is converted, and control the display to display the image-quality-processed first image and the OSD image.