It has developed a fair bit since…
…was created in December 1975 by an engineer at Eastman Kodak named Steve Sasson (guy on above pic). In a Kodak blog post written in 2007 he explains how it was done:
“It had a lens that we took from a used parts bin from the Super 8 movie camera production line downstairs from our little lab on the second floor in Bldg 4. On the side of our portable contraption, we shoehorned in a portable digital cassette instrumentation recorder. Add to that 16 nickel cadmium batteries, a highly temperamental new type of CCD imaging area array, an a/d converter implementation stolen from a digital voltmeter application, several dozen digital and analog circuits all wired together on approximately half a dozen circuit boards, and you have our interpretation of what a portable all electronic still camera might look like.“
The camera weighed 8 pounds (3.6 kg), recorded black and white images to a compact cassette tape, had a resolution of 0.01 megapixels (10,000 pixels), and took 23 seconds to capture its first image in December 1975.
To play back images, data was read from the tape and then displayed on a television set.
Via Petapixel, 3dfocus, Wikipedia