Editors only want to see manuscripts. In fact they don't like writers to send illustrations (unless they are illustrating the book themselves). Editors will do the rest, like find a matching illustrator and take it from there. They are very good at that and have a sense of what works and sells.
I can imagine that sometimes is not easy for a writer to understand this because they see their story as their baby and I am pretty sure they had images behind those words when they wrote them down.
But you have to trust the editors, they know what they are doing.
