A method of creating an image identifier of a target image. The method comprises providing a target image, identifying a plurality of connected component clusters in the target image, each the connected component cluster comprises a plurality of neighboring pixels having at least one common property, calculating a center of gravity for each the connected component cluster, generating an image identifier of the target image by using a plurality of elements to map the connected component clusters in a space, each the element represents a respective the at least one common property, a respective the center of gravity, and a size which corresponds with a number of the plurality of neighboring pixels of the respective the connected component cluster, and outputting the image identifier.