Copyright is an unregistered right (unlike patents, registered designs or trade marks). So, there is no official action to take, (no application to make, forms to fill in or fees to pay). Copyright comes into effect immediately, as soon as something that can be protected is created and “fixed” in some way, eg on paper, on film, via sound recording, as an electronic record on the internet, etc.
The UK Patent office classes a photograph as a work that copyright protects, along with other original artistic works such as paintings, engravings, sculptures, collages, works of architecture, technical drawings, diagrams, maps and logos
Also, the above terms are regardless of the medium in which they exist and this includes the internet.