It’s a unique opportunity when an illustrator can also write stories that other artists can render. This happened to Don Tate when he wrote It Jes’ Happened, illustrated by R. Gregory Christie.
Check out this excellent discussion between Anne Rockwell and Don Tate, at Anne’s site.
“…While I could have illustrated the story, my illustration styles weren’t the perfect match for the text. My editor wanted the art to be edgy, gritty. I wanted to go with an illustrator who had broader name recognition than myself. Greg Christie became one of our top choices.”—Don Tate
Remember this if you encounter a book editor who loves your story, but suggests that another illustrator provide the art. Don’t insist on all (doing both story and pictures) or nothing.
If a publisher is seriously interested in acquiring one component, make sure to ask why. Decisions like these are made for the good of the project.
Editors want your book to sell as many copies as possible. One practical consideration is name recognition. Newcomers tend to forget that buyers invariably prefer to request a familiar name or brand, when they shop, even in bookstores or libraries. Publishers also need to see how your name fares out there initially, in the mutual interest of nurturing a new career for the long term.