An illustration is like a fingerprint and is possible to recognise the illustrator from an illustration. Here is some examples.

Mabel Lucie Attwell-tiny children, pixies (signed).

Arthur Rackham: Dark colours, rather gothic in style.

Harry G Theaker: Pastel shades.

Aubrey Beardsley: Black and white, floral border

Kate Greenaway: bright colours, as if a toy theatre

William Heath-Robinson: Black and white, shows contraptions

Beatrix Potter: Natural colours, animals.

Maxfield Parrish: Like a stained glass window, shades that may not quite seem right.

Gwynnedd Hudson: Resembles old fashioned Christmas cards, 3D look, will have illustrations on the headline (the top of the page).

Margaret Tarrant: Similar to Kate Greenaway, but more defined illustrations.

E H Shephard: Black and white line drawings with fuzzy edges.

John Tenniel: Black and white images, notable shadows and patches of light.