Copyright means that when a designer, illustrator, photographer, or other visual artist, creates an original piece of artwork, that person owns the right to make copies it.
Even if the creator sells the artwork, they retain the copyright to it. The moment the artwork is created, the copyright is created. There is no required process to register a copyright — although if you do create something, it's a good idea to register it, which can be as easy as
The creator retains the right to reproduce their artwork, copy it, display it in public, and to benefit economically from it. The creator also has the right to prevent someone else from copying or using the image.
The creator may permit others to use their images by granting them a license, which is a written agreement which details ow the client may use the image, for how long, in what manner, and how much the client will pay for the image.
Patents protect procedures, processes, systems, and/or methods of operation, where copyrights protects only expressions of ideas. So, even if Marie Kondo copyrights a book on organizing, she can't sue you for rolling your clothes.
In 1976, copyright lasted for the life of the author plus 50 years, or 75 years for a work of corporate authorship. In 1998, the Copyright Term Extension Act extended the term to the author's live plus 70 years and corporate authorship to 120 years after creation or 95 years after publication, whichever ended first. Basically, Disney is responsible for lobbying and passing the act to keep Micky Mouse out of the public domain.
Many artist feel that this is ridiculous, and prevents works from entering the public domain that should be there for everyone to use. In response, many artists are looking for fairer ways to protect their work, and many have turned to:
There are several organizations that are trying create a fairer system. My favorite is Creative Commons, which allows various types of licenses to be created for artwork. You answer a series of questions about how you want your work protected, and Creative Commons creates a custom license that you attach to your artwork.
In any and all cases of using images for a project, if you're making money with it, you must respect the work of others and give them their fair due. Wouldn't you want the same courtesy applied to you?