Select a photo that has a good amount of detail, especially if you are writing a longer piece. The more detail in a picture, the more information you have to write about.
Give your students a list of topics to write about. This list should target things found in the picture, or ways to write about the photo. For example, you could ask students to write about the mood conveyed by the photo, the thoughts of the people or animals in the photo, what happened prior, during and after the picture was taken, and what caused a certain reaction captured in the photo.
Ask the students to write their answers to these questions in full sentences. Some photos may be more conducive to answering certain questions than others, but they should try to answer all questions to the best of their ability.
Combine the answers to the questions into a story. The students should have a story outline which tells what happened before, during and after the photo was taken, which will be the story line for their writing assignment. They should also have a description of the character or characters in the story and have a basic understanding of how they interact.
Assist your students in placing the concepts of the story in a logical order to complete the story. You may need to help them rearrange certain aspects to help the story flow more naturally and read less like a simple description of the photo. This can also serve as a lesson in editing a writing assignment.