Level 1 Sixel Graphics

  By default, a Sixel introducer that omits the macro parameter
  is selected.  This option does not use the Sixel Set Attributes
  command to set the aspect ratio and the horizontal grid size.
  As a result, the Sixel aspect ratio is 2 to 1 and the horizontal
  grid size is approximately 188 x 0.025 mm (7.5 x 0.001
  inches).