20 Illustrations for a Childs book

Hi,
I'm writing a rhyming book for my 3 year old and his two friends and I'm looking for 20 illustrations to be included. I would like the characters to be based on themselves and their parents and dog (I will supply photos!). The 20 illustrations includes front and back covers. Attached is the style of illustrations I like but open to other ideas.

Please let me know if I have missed anything, I will, of course provide the copy as soon as it's finished. I will be editing the book myself so illustrations need to be supplied in PNG format.