Nowadays, Internet has made our life easy and convenient. The accessibility of multimedia data such as audio, images and videos has been increased. But due to this explosive growth in this technology, the data can be deleted, modified or plagiarized easily without proper authorization and authentication. So multimedia security has become a extreme concern in this internet technology. Digital watermarking is the field of information hiding  which hides the crucial information in the original data for protection, illegal duplication, distribution of multimedia data. It increases the robustness to various attacks and should ensure that this watermark is imperceptible. This paper presents a literature survey of digital watermark used for the images, including the analysis of various watermarking techniques and their applications.