"19. In our judgment, on the authorities, there are, as it seems to us, at least four circumstances in which, subject to the judicial discretion to exclude, evidence is admissible to show and, subject to appropriate directions in the summing-up, a jury can be invited to conclude, that the defendant committed the offence on the basis of a photographic image from the scene of the crime: (i) where the photographic image is sufficiently clear, the jury can compare it with the defendant sitting in the dock (Dodson & Williams); (ii) where a witness knows the defendant sufficiently well to recognise him as the offender depicted in the photographic image, he can give evidence of this ( Fowden & White, Kajalave v Noble, Grimer, Caldwell & Dixon and Blenkinsop); and this may be so even if the photographic image is no longer available for the jury (Taylor v The Chief Constable of Chester); (iii) where a witness who does not know the defendant spends substantial time viewing and analysing photographic images from the scene, thereby acquiring special knowledge which the jury does not have, he can give evidence of identification based on a comparison between those images and a reasonably contemporary photograph of the defendant, provided that the images and the photograph are available to the jury (R v Clare & Peach); (iv) a suitably qualified expert with facial mapping skills can give opinion evidence of identification based on a comparison between images from the scene (whether expertly enhanced or not) and a reasonably contemporary photograph of the defendant, provided the images and the photograph are available for the jury (R v Stockwell(1993) 97 Cr App R 260 , R v Clarke[1995] 2 Cr App R 425 and R v Hookway [1999] Crim LR 750)."