  As digital content can be copied easily, Copyright infringement has become a
concern nowadays. Providing a solution to prevent the abuse of such contents is
very necessary. One of the most common methods to solve this problem is
watermarking. In this method, a logo belongs to the owner of the media is
embedded in the media. So, they can prove the originality or ownership of the
media content. Images are one of the most important digital media. Therefore,
in this study, a method for digital image watermarking is proposed. The
proposed method is based on Graph-based Transform (GBT), Singular Value
Decomposition (SVD), and Discrete Wavelet Transform (DWT) which uses a Whale
Optimization Algorithm (WOA) to find the best value for the embedding
coefficient in the images as well as optimal blocks. The image is first
transformed to a transform domain using the DWT and GBT, and then the watermark
logo embedded onto the singular values of the cover image. The objective
function defined for this task is based on the three parameters PSNR and NC, in
the presence of image attacks. The results of the proposed algorithm on some
known images show a high performance of this method compared to other similar
methods.
