There are varying styles of writing your essay. Remember that the purpose of a descriptive piece is to bring your story, make the imagination flow and make the reader believe, enjoy and understand your thoughts.
First Person: i.e. use of yourself as the main person telling the story. In these types of stories, the author will refer to himself in the first person, i.e. “I” or “we” or “our.” This is really used when the person has decided to use himself as the victim/author/narrator of a situation or story or event that has happened.
Third Person: i.e. writing the story through the eyes or experiences of another person as the main character. The writer will refer to the character as “he” and use words like “they” or “them or “theirs.”
Reflective: i.e. use of main character being in the present but is thinking about a situation that happened to him/her in the past. This can be ideal for picture essays. For e.g. the examiner may present you with a picture of a child crying, or a house burning and you can use the reflective style as if someone is looking at the picture and telling the tale behind that picture/actions in the picture.