The D2IMFILE reference file is a 2-D look-up table that contains astrometric corrections for shifts induced by the lithographic-mask pattern that was imprinted on the UVIS detector during the manufacturing process. This correction table is used in coordinate transformations prior to applying the large-scale polynomial geometric solution (IDCTAB). The look-up table is incorporated by running updatewcs (via AstroDrizzle) with the filename specified in the D2IMFILE keyword in the primary image header, which will then be attached to the image as a fits extension of type 'D2IMARR' (four extensions total, two for each chip and dimension). Each element of the 32x17 table gives the astrometric xy shift in pixels to apply at a particular location on the detector. The latest IRAFX release (May 20, 2013) was updated to allow AstroDrizzle to interpolate across a 2-D table grid, and hence only this IRAFX version (and later) can apply the D2IMFILE corrections.