The small imaging device has a data receiver configured to receive the reference encoded image data. The data includes reference code values encoded by an external coding system. The reference code values represent the reference gray levels and the reference gray levels are selected using a reference gray scale display function based on perceptual non-linearity of human vision adapted to different light levels for spatial frequencies. The imaging device also has a data converter configured to access code mappings between the reference code values and the device-specific code values of the imaging device. The device-specific code values are configured to generate gray levels specific to the imaging device. Based on the code mapping, the data converter is configured to transcode the reference encoded image data into device-specific image data encoded with device-specific code values.