Oldest picture ever taken.
 
circa 1826), taken and developed by French photographer pioneer Joseph Nicéphore Niépce. He called this process "heliography" or sun drawing – it certainly was a long process: the exposure time was about 8 hours.

Worlds oldest photo of a human.
This is one of the, if not the, oldest known photograph of a human being in existence. It depends on how one defines photograph, but this was taken by Louis Jacques-Mande Daguerre in 1838

 
First human portrait:
In 1839, Robert Cornelius, a Dutch chemist who immigrated to Philadelphia, took a daguerreotype portrait of himself outside of his family’s store and made history: he made the world’s first human photograph!

 
Now the cool stuff.
 

http://www.neatorama.com/2006/08/29/the-wonderful-world-of-early-photography/