A digital image is obtained from a camera in a smartphone and is processed by a processor on the smartphone to modify a part but not all of the pixels in a frame of the digital image, which is a digital video image, which is modified by image processing in accordance with a modification mask and reversible modification instructions, and is transmitted to a second smartphone with a display screen to display the modified image. Image processing data are transmitted to the second smartphone to enable restoring the original digital video image from the partially reversibly modified image and to be displayed in unmodified form on the display screen.