My avatar is a political piece from the 1864 presidential election. It is called a ferrotype. The images of Lincoln and his running mate, Andrew Johnson, on the reverse were printed on thin sheets of iron which these pieces their makes. Multiple images were reproduced on a single sheet, cut into individual pictures and then mounted on brass frames.
The first ferrotypes appeared in 1856, but those pieces are so rare that barely any collectors have one. I have only seen one picture of a piece that was for Millard Filmore who ran for the American or “Know Nothing” Party that year. They really came into their own for the 1860 election. Here is an 1860 Stephen Douglas ferrotype
And here is an 1860 Lincoln ferrortype. You will notice that Lincoln did not have his trademark beard. The photo was cropped from the Mathew Brady picture taken of Lincoln when he made is speech to the Cooper Union in February 1860.