if someone took screen shots of my facebook post with my name and picture and then proceeded to talk trash about me is that considered slander>

Depends.  To be slander, the "trash" has to be untrue and derogatory statements of fact, not opinion.  So the statement that "John is a convicted thief" could be slander, but the statement that "I don't trust John" is not.  Also, depending on what was said, the person suing for slander may have to show that he/she suffered actual monetary damage due to the slander, for example that they were fired and therefore lost two weeks pay before they got a new job.