Some film histories erroneously cite this as the first animated cartoon, ignoring not only Humorous Phases of Funny Faces (1906) (probably the first true animated cartoon), but even Winsor McCay's own earlier work, Winsor McCay, the Famous Cartoonist of the N.Y. Herald and His Moving Comics (1911) and How a Mosquito Operates (1912).
The first movie featuring a dinosaur.
This film required Winsor McCay and his assistant John A. Fitzsimmons (who traced the backgrounds) to create 10,000 drawings, which they inked on rice paper and mounted on cardboard. Although later animators created techniques (such as the "slash system" and especially celluloid-over-paper) that would eliminate the need to redraw backgrounds or stable objects, McCay was working without precedents. Consequently, he chose to redraw the entire picture-- Gertie and the richly-detailed background-- for each frame.
Winsor McCay's employer, William Randolph Hearst, was displeased with McCay's success outside of the newspapers, and used his contractual power to reduce McCay's stage activities. In late 1914 William Fox offered to market the film to moving-picture theaters. McCay accepted, and extended the film to include a live-action prologue and intertitles to replace his stage patter. This is the version of the film generally seen nowadays; the original animation comprises roughly five minutes of the entire 12-minute film.
Selected to the National Film Registry, Library of Congress, in 1991. It was the oldest animated short to be preserved at the time until Winsor McCay, the Famous Cartoonist of the N.Y. Herald and His Moving Comics (1911) was selected to be preserved 18 years later.