What is the effect of still photographs of a suspect being shown to a witness prior to a live lineup?

People v. Johnson is particularly apt. There, police were investigating a series of robberies or attempted robberies of gas stations in the Sacramento area. Still photographs taken from the video surveillance recording of one of these incidents were shown to the victim of an uncharged incident, and she recognized the subject in the photographs as the person who attempted to rob her. (People v. Johnson, supra, 183 Cal.App.4th at p. 271.) She subsequently identified the defendant in a live lineup. (Ibid.) Rejecting the contention that use of the photographs before the live lineup improperly tainted the witness's identification, the court first noted that because the photographs were not part of the record, it did not know exactly what they depicted and therefore could not determine what prejudicial effect they could have had on the subsequent identification. (Id. at pp. 272-273.) The court then stated, "We certainly cannot say the procedure was unnecessary. A police sergeant from a different jurisdiction asked Mar to view the photos based on the similarity in the crimes and in order to solve the crime against Mar." (Id. at p. 273.)