The protection of ownership and the protection of unauthorized tampering of multimedia data (audio, image, video, and document) have become a major concern for the authors of multimedia. Image authentication verifies the originality of an image by detecting malicious manipulation The protection of ownership and the protection of unauthorized tampering of multimedia data (audio, image, video, and document) have become a major concern for the authors of multimedia. Image authentication verifies the originality of an image by detecting malicious manipulations. Digital watermarking researches have generally focused on two classes of watermarks, Fragile and robust. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the water marked images. Robust watermarks are designed to be detected even when attempts are made to remove them. In This paper, we focus on the first class of watermarking for digital images authentication by creating a mark based on the self similarities blocks properties of fractal encoding. We start with fractal encoding algorithm, then, partitioning the tested image into ranges and domains blocks, finding the pieces of ranges and their corresponding domains by minimizing the distances between them, finally, we create the mark by partitioning the same image into four columns of equal size and compute the mark through the determination of location for domain block parameters in which column number occurs.