"Printers used woodcuts to print illustrations by the relief process and experimented with intaglio in copper engravings. Woodcut pictures were produced before metal types, and it was a simple development to make woodcuts in appropriate dimensions for use with type to print illustrated books." -Another website
Rephrased:
Early printers used woodcuts to display images by the process of relief- this was experimented by intaglio in copper shapes and strokes. Woodcut photographs were made before mineral and metal options, and it was basic development to form woodcuts correctly to be used in making book illustrations and designs.
*Hope it helped :)
