The Viking lander cameras acquire data in six spectral bands for color and neat-IR imaging with an angular resolution of 0.12¿ and for broadband imaging with a resolution of 0.04¿. Accurate determination of spatial and spectral brightness variations from image data depends both on calibration and on evidence of calibration stability. A 'rubber sheet transformation' is used to correct camera-dependent geometric errors. Edge matching between pictures taken with different photodiodes and parallax errors less than three picture elements for distant objects indicate that the calibration for this transformation is still valid. The absence of aliasing effects despite undersampling indicates that most surface particles are less than 0.3 mm in diameter. Radiometric measurements have been corrected for significant photodiode degradation due to neutrons from the radioisotopic thermoelectric generators. Vignetting occurs between +25¿ and +40¿ elevation, and false 'clouds' caused by light scattered from the camera's outer housing may appear between +12¿ and +20¿. Contouring, most noticeable in uniformly bright areas, is caused by quantization of the photodiode signal.