1. A digital memory for an image to be displayed by systematic point by point and line by line scanning of a television type screen, the memory being comprised of N blocks, each block containing data for the image, an address counter and a read out register connected to said memory, said address counter receiving clock pulses for synchronizing a read out operation of the memory to a writing operation on the screen, to thereby extract display data successively from all the memory blocks, said address counter receiving an additional counting pulse every time a full line has been written on the screen, said blocks being read cyclically so that successive read out operations concern different blocks.