Portraiture is a graphic and detailed description of a subject, especially a person.

If the selfie is a graphic and detailed representation of oneself, it can become portraiture.

In a portrait, the eyes, facial expressions, body movement, and background should be included. Things that do not contribute to the representation of the identity of the subject should not be included.

In a good portrait, the subject’s emotions are expressed fully, through the eyes, the facial expressions, the body movement/pose, and the background. The audience/viewer can infer clearly what message the photographer is trying to send out.

If a photo only consists of a close-up shot of a hand, unless it suggests something about the subject, it is not a portrait.

When an abstract photograph cannot clearly show the characteristics or the emotions of the subject, then it ceases to be a portrait.

Using still-life objects can surely still represent a person, though it might be a bit difficult to understand. As long as the objects can represent a person well, they can still be called portraits.

A portrait can surely be a sequence of images, as long as they are relevant to the subject and the emotions and characteristics of that subject.