When giving permission to use their work, some copyright holders ask that you do this. In some cases, you may also need to credit the copyright holder if you plan to use their work in a way that you consider fair use or fair dealing. However, this doesn't automatically give you the right to use the content without permission.
Owning a copy means you might be able to sell that copy or give it to a friend, but it doesn't give you the right to publicly share that content with the entire internet.
