JEITA  CP-3451 - 127 - Recording  of  restart  markers  is  optional,  and  conversion  to  Flashpix  is  possible  without  them;  but  conversion without restart markers may result in some image quality loss and require a longer processing time. In  order  for  restart  markers  to  be  inserted  at  64-pixel  Interoperability,  the  image  data  width  shall  be  an  exact multiple of 64. Therefore the valid image width is recorded as tag information (PixelXDimension), and the JPEG compressed  data  is  recorded  with  the  valid  image  padded  to  the  right  to  make  it  an  exact  multiple  of  64  (see section 4.8.1). As  in  the  Flashpix  standard,  padding  is  used  where  necessary  to  achieve  exact  multiples  of  64;  and  when converting to Flashpix, the padding data on the right can be treated in the same way as valid image data. If the image height is not an exact multiple of 64, Exif files are not padded; so when converting to Flashpix it is necessary to pad the bottom edge of the image. Figure 55 Image Size Restrictions SOF Y = PixelYDimension (APP1) Padding Data SOF X PixelXDimension (APP1) JPEG Data 64x64 Block (FPX tile)