This thesis will explore the protection of photograph copyright owners. Photograph copyright facilitates the protection of original intellectual property of artistic content that shows individual character regardless of the manner and form of expression, its value or purpose, unless otherwise specified by law. The growing presence of the Internet brings about frequent illegal use of photographs, i.e. use without the author's knowledge. This problem is examined from a legal side in order to emphasize the rights an author is entitled to after having protected his own property. The most common form of photograph copyright is the digital watermark whose function is to embed bits of information into the original photograph in the interest of protection. Another important element are the agencies that take care of the authors and their copyright of authorship. They facilitate the protection of the photographs and the author's right to gain profit, a right he is granted by the copyright laws. The thesis paper also contains a research in which a digital watermark was created only to be tested in Photoshop with a series of different methods of attacking. The test showed to what extent the digital watermark is immune to attacks. The main purpose of the research itself was to show the degree of security the digital watermark provides.