Some children struggle with creative writing so why not get them to create their own photo to write a story about.
Children select a background that they would like to paste themselves into. Choosing a picture first, means that you can discuss camera angles with children and body positioning so that their photo best fits into the background. I have had children take photos from a low angle so that they appear as a scary giant or from a high angle so that they come across as a small dainty fairy. Children have also sat on chairs with their legs out and arms up as though they are sliding down a rainbow.
Once children have taken their photo, they can place themselves into their background and write a creative story that fits the image. For example, a student trying to bust out of a bubble may write about how they got into the bubble or how they've spent their day inside the bubble.