A method of operating an electronic device is provided. The method includes receiving, by a display driving circuit of the electronic device, main image data over a first channel from a first processor or a second processor of the electronic device, outputting, by the display driving circuit, a main image on a display panel of the electronic device based on the main image data, generating, by the display driving circuit, an additional image different from the main image, and merging, by the display driving circuit, the main image with the additional image and outputting, by the display driving circuit, the merged image on the display panel.