A method for generating an image for a display device comprising a display screen and a graphics generation unit performing at least three functions for displaying an image, a first function of erasing, a second function of generating an image made up of pixels in a first memory and a third function of displaying the image and of controlling the screen, an image is divided into a plurality of distinct zones of pixels and each zone is addressed by a flag, and the display device further comprises a second memory saving the state of the flags allowing the graphics generation unit to execute the display function as a function of the state of the flags, the first function of erasing being a function of erasing from the second memory, the method being characterised in that the flags encode two states of the pixel zones: • a first state if the addressed pixel zone comprises at least one pixel that has been written by the image generation function; • a second state if no pixel of the addressed pixel zone has been written by the image generation function, this second state allowing the display function to assign a default value to the pixels of the zone, the default value assigned by the display function to the pixel zones for which the flag is in the second state being the value that encodes the background frame of the image; the method comprising the following steps: • in a first "ERASE" step, the graphics generation unit performs the first function of erasing flags from the second memory, the flags are then encoded in the second state; • in a second "GENERATE" step, the graphics generation unit executes the second function of generating the image in the first memory and at the same time encodes, in the second memory, the state of the flags of the written pixel zones, the state of the flags being encoded in the first state; • in a third "DISPLAY" step, the graphics generation unit executes the display function, which, by consulting the flag memory, reads, in the first memory, the pixel zones for which the flag is in the first state and provides the default value to the pixels of the zones for which the flag is in the second state, with the display function reading, only in the first memory, the pixel zones for which the flag is in the first state. • a first state if the addressed pixel zone comprises at least one pixel that has been written by the image generation function; • a second state if no pixel of the addressed pixel zone has been written by the image generation function, this second state allowing the display function to assign a default value to the pixels of the zone, the default value assigned by the display function to the pixel zones for which the flag is in the second state being the value that encodes the background frame of the image; • in a first "ERASE" step, the graphics generation unit performs the first function of erasing flags from the second memory, the flags are then encoded in the second state; • in a second "GENERATE" step, the graphics generation unit executes the second function of generating the image in the first memory and at the same time encodes, in the second memory, the state of the flags of the written pixel zones, the state of the flags being encoded in the first state; • in a third "DISPLAY" step, the graphics generation unit executes the display function, which, by consulting the flag memory, reads, in the first memory, the pixel zones for which the flag is in the first state and provides the default value to the pixels of the zones for which the flag is in the second state, with the display function reading, only in the first memory, the pixel zones for which the flag is in the first state.