It is difficult to correctly diagnose head lice infestation by using pictures alone. The most accurate method of diagnosing head lice infestation is by finding a live nymph or louse on the hair or scalp of a person, as stated by the Centers for Disease Control and Prevention.
The presence of nits does not always confirm an active head lice infestation, according to CDC. Since nits need heat from the scalp to incubate, nits that are found more than one-fourth inch from the scalp are often dead or hatched. Nits located near the tips of the hair are usually indicative of an inactive infestation, which does not need treatment. Also, dandruff and dirt particles are often mistaken for nits.