The article presents a novel fragile watermarking scheme based on the concept of pixel differencing for the integrity verification of digital images. The scheme uses the human visual system to embed the authentication data into the difference between the input pixel and the average of its neighbouring pixels. The new scheme is capable of outperforming others because it not only provides a securer, more efficient detecting procedure, but also offers better resultant image quality. To demonstrate how well the new scheme can work in detection ability and security, some experiments and security analyses are also included.