To protect your photos with copyright, you can follow a few steps. First, you can register your photographs with the US Copyright Office. Technically, any photograph that you take automatically belongs to you for a minimum of 25 years, but to formally register your images, you will need to visit Copyright.gov and click Learn More in the Register Your Works module. You can either complete the application form online or with a hard copy that you must mail to the US Copyright Office.
Another way to protect your photos is to place a copyright symbol and notice on them. This is a simple and free way to establish possession and protect your work. You can also use a poor man's copyright by notarizing your work or sending it to someone, even yourself, via email or another method. This helps to establish possession and may be useful in case of any disputes.
It is important to note that to register a copyright, your image needs to meet certain criteria. The image needs to be an original work and has to be a tangible object, such as a digital photograph. It cannot just be an abstract concept like the idea of an image. Additionally, when you sell your photo or image as an NFT, you may continue to retain copyright. However, it is recommended to consult with a legal professional to ensure that your photos are fully protected.