1. paint by numbers - Adjective
2. paint by numbers - Verb
To complete a painting by numbers kit
(figuratively) To perform something in the simplest way
(of a picture) Made from a painting by numbers kit.
(figuratively) By rote, without thought or creativity.
Source: en.wiktionary.orgpaint-by-numbers
Bruce C. Murray used photographs from Mariner 4 to elucidate Mars' geologic history. citation The first digital image from Mars hand-colored like a paint-by-numbers picture The first digital image from Mars The first close-up image ever taken of Mars. Source: Internet
While waiting for the image data to be computer processed, the team used a pastel set from an art supply store to hand-color (paint-by-numbers style) a numerical printout of the raw pixels. Source: Internet