The document discusses the history and techniques of digital images and photomontage. It covers: - In the 1920s, Dadaists used photomontage to express modern life by combining actual photographs. - Digital images are made of pixels in a grid, unlike analog images which are continuous. Digital images can be manipulated more easily with tools. - Local touch involves accumulating small marks over time, while global touch instantly changes large areas. - Key digital image concepts discussed include tonal mapping, filtering, transformations, selections, composition, resolution, scaling, color depth, and alpha channels for transparency.