Since https://victorianpoetrypoeticsandcontext.wikispaces.com/ edited by Alison Chapman will be shut down together with wikispaces.com on 2018-07-31, I mirror their wiki page on the Lewis Carroll Picture Book in my blog and quote a paragraph on Illustrated Poetry in the Victorian Period:
Advances in technology made it possible for any given literary volume to be published en masse, thus expanding the book market extensibly. Previously, manuscript copies of a writer’s work were limited, due to the laborious effort it took to recreate these volumes; however, following the invention of the printing press, books became less of a luxury item, and, therefore, more accessible to less wealthy households.
This caused value to shift from the rarity of a book to its other additive qualities, spurring a tradition of adding corresponding illustrations to increase a books’ aesthetic appeal. Publishers encouraged 19th century writers to include pictures alongside their prose and poetry in order to draw in greater profit for themselves: these companies anticipated greater sales of an illustrated volume that of its unembellished counterpart, and were able to attach a higher price tag to each of these lavish copies.
Despite this pressure and undeniable popularity, poets were often still hesitant to publish their works accompanied by such adornments due to the notion that visual aids might skew the reader’s perception of the verse.
The choice of Stuart Dodgson Collingwood to include his uncle’s personal sketches [in the Lewis Carroll Picture Book (1899)] indicates an attempt to appeal to the gift book market, and, further, reveals the publisher’s own aspiration to profit monetarily from his personal relationship to Lewis Carroll– notorious author and poet, but lesser-known sketch artist. Through composing this augmented edition of Carroll’s most prominent titles, Collingwood undoubtedly capitalized on this pre-established celebrity while simultaneously preserving his uncle’s notoriety.
(Alison Chapman credits the wiki page on the Lewis Carroll Picture Book to an undergraduate student who prefers to be anonymous.)