Nowadays, image authentication schemes are widely applied to ownership protection and tampering detection of digital images. In this paper, we propose an image ownership and tampering authentication scheme based on watermarking techniques, which is employed to protect the rightful ownership and detect malicious manipulation over embedded images. In the scheme, the authentication data of an image will be inserted into adaptive least significant bits of the embedded pixels. And the number of the least significant bits will be determined according to the type of the corresponding block. The experimental results show that the quality of the embedded image is very high, and the positions of the tampered parts are located correctly.