John Logie Baird at the Science Museum in London, circa August 1926, with his "televisor".

On January 26, 1926, John Logie Baird, a Scottish inventor, 
gave the first public demonstration of a true TV system
in London, launching a revolution in communication and
entertainment. Baird’s invention, a pictorial-transmission
machine he called a “televisor,” used mechanical rotating
disks to scan moving images into electronic impulses.

This information was then transmitted by cable to a screen
where it showed up as a low-resolution pattern of light and
dark.  Baird’s first television program showed the heads of
two ventriloquist dummies, which he operated in front of the
camera apparatus out of view of the audience.

.

This image is the first recorded picture taken from a TV
screen.

John Logie Baird  (1888 – 1946)