William Henry Harrison was photographed on his Inauguration Day in 1841,making him the earliest known POTUS to be photographed while in Office.

There were obviously earlier Presidents photographed,but after they had left office.

The photograph above is a digital scan of the Copy held by the New York Met. Museum,and is the only known copy in existence,though it’s thought there were many more.

Kind of Ironic how the most inconsequential president was the first to be photographed in office.