A person's self image is the mental picture, generally of a kind that is quite resistant to change, that depicts not only details that are potentially available to objective investigation by others (height, weight, hair color, sex, I.Q. score, etc.), but also items that have been learned by that person about himself or herself, either from personal experiences or by internalizing the judgments of others. A simple definition of a person's self image is their answer to this question - "What do you believe people think about you?" A more technical term for self image that is commonly used by social and cognitive psychologists is self-schema. Like any schema, self-schemas store information and influence the way we think and remember. For example, research indicates that information which refers to the self is preferentially encoded and recalled in memory tests, a phenomenon known as "Self-Referential Encoding" (Rogers et al. 1977).
The formation of a healthy self image can be challenging for an individual, especially when family, peers, community, or the general society issues very negative evaluations of a person. The consequences can be severe for the individual, who may learn self-hatred. They can also be severe for the society.
Poor self image may be the result of accumulated criticisms that the person collected as a child which have led to damaging his own view of himself. Children in particular are vulnerable to accepting negative judgments from authority figures because they have yet to develop competency in evaluating such reports.
It should be noted that some information about an individual is not directly available to others, and that information may be very pertinent to the formation of an accurate and well functioning self image. For instance, only the individual may know whether certain of his or her acts were malicious or benevolent in intent. Only individuals know whether in their internal experience they are masculine or feminine, good or bad and so on.
Individuals often form a negative self image as a result of physicalities affecting themselves, such as alcoholic parents or other unstable environments, and the use of drugs to unintentionally hurt themselves.
Residual self image is the concept that individuals tend to think of themselves as projecting a certain physical appearance. The term was popularized in fiction by the Matrix series, where persons who existed in a digitally created world would subconsciously maintain the physical appearance that they had become accustomed to projecting.