Optical imaging systems or cameras have a convex lens with limited depth of field. So, multi-focus images are obtained when such systems are used to capture an image of a particular scene. These images are fused to get all-in-focus image. This paper proposes a new simpler method of multi-focus image fusion. Instead of decomposing input image into blocks in pyramid style, the proposed algorithm considers the complete image for edge detection. The proposed algorithm uses the genetic algorithm (GA) to find out the optimum weights from extracted edges and then fuses the images with the fusion rule based on optimised weights. Experimental results show that this superimposition method performs well; consumes less computation time and thus proves to be suitable for hardware implementation