Digital illustrations/graphics for children book/app

I need a Freelancer to create illustrations/images for use in a kind of children book/app (for kids 6-8 years old). These are the demands for this project: 1. Illustrations/images must be distributed to me digitally in ”.png” format. 2. The images must have the size of 1500*1500 pixels (72 dpi). 3. Each of the illustrations/images will have a part of a story to illustrate. They are basic images without that much details. There are a total of 6 different stories with one main "character" in each story - a snake, a monkey, a car, a ghost, a monster and a train. Each story consist of 40 different images, but each of them are consisting of the main character and there are only minor differences in many of them (for example one image with a blue snake, one with a green snake and so on). I will provide more details to interested bidders. 4. Good english writing skills for communication is needed. 5. All work must be done for this project only and are not to be re-used in any way. The copyright for the images must be transfered to me upon delivery. 6. The Freelancer must, within the project budget, be willing to make minor adjustments to the illustrations if required. Please provide examples of previous illustrations you have done. Experience from working with illustrations for children is a plus.