1. A method of processing graphical image data representing optically scanned medication-related units comprising: receiving image data generated responsive to disposal of the units on a tray disposed a distance from an image acquisition component, the image data including data indicative of visually observable features of the units disposed on the tray; comparing, via processing circuitry, at least two features among the visually observable features from the image data to reference data indicative of corresponding features of reference units, the reference data being selected for comparison based on an identification of the reference data as corresponding to a prescription being processed, the reference data including data indicative of features of the reference units extracted from images captured using hardware corresponding to hardware used to generate the image data; and generating a likelihood rating for each of the at least two features based on the comparing.