1. A computer-implemented method for measuring image quality, comprising: receiving a composite image, wherein bits of one or more pixels of a first image are perturbed to generate the composite image in which a plurality of reference images are hidden in the first image via perturbations, and wherein a respective one of a plurality of bit positions is perturbed to hide each of the reference images; recovering, from the composite image, the perturbations; and determining a quality of the first image in the received composite image based on at least a lowest of the plurality of perturbed bit positions for which quality of a corresponding one of the hidden reference images meets a predefined threshold value, wherein quality of each of the hidden reference images is determined based on at least a comparison of recovered perturbations representing the hidden reference image and a corresponding stored reference image.