The protection of digital information has drawn significant attention in recent years. Data authentication and copyright protection issues are widely considered as two major concerns. Digital watermarking can be considered as a solution to ensure copyright protection and data authentication in which a watermark will be embedded into a digital content. Later, the watermark can be extracted to ensure copyright protection or to ensure data authentication. Robust watermarking schemes are widely used for copyright protection of digital content and fragile watermarking schemes are preferred for data authentication. The purpose of this work is to provide a thorough analysis of the domain of research regarding image watermarking methods. This manuscript gives an overview of the digital image watermarking approach, the classification of digital image watermarking schemes, and the research challenges in this domain.