As part of the huge trove of public domain images being posted on Flicker — which I reported in 2013 — the British Library has assemble a large collection of children’s book illustrations.
As is often the case with these kinds of large scale image resources, best results come from a bit of patience and digging.
Some of the illustrations are not directly attributed to the artists, but reference is given to the books from which they were taken.
[Via DCAD Library and Century Past History on Twitter]