While a bank clerk at Whitchurch, Shropshire, Randolph Caldecott began drawing for local magazines. Through his acquaintance with George Du Maurier he began contributing to the periodical London Society in 1871; the next year he settled in London and turned professional, ultimately drawing for Punch and Graphic, among other periodicals. He increased his skill by painting under Sir Edward Poynter and by sketching and modelling in the studio of J. Dalou.
In 1872 he went with his lifelong friend Henry Blackburn to Germany. His coloured picture books for children included W. Cowper's John Gilpin (1878), Oliver Goldsmith's Elegy on a Mad Dog (1879) and The Great Panjandrum Himself (1885). His works in other media include paintings, metal reliefs, and terra-cottas. (Taken from GMPD).
Caldecott frogs are pretty famous. For instance,