A source that is written or created by a person who experienced an event personally is called a primary source.
Pimary source is like the original piece that was seen at a given time and place personally. If the writter or artist wasn't there, and has no idea or understanding of the event, this is called secondary source. When the writter is trying to put some insufficent informations or propaganda infos to make people belief it is true, this is called biased source. (Just like Paul Rivera photo I believe)
Hopefully this helped! ;D
