When Previewing, sometimes some parts of the lines in the read in PostScript image disappear. This is because the color BMP image created by Ghostscript is compressed by a function provided by Windows and displayed (this is due to the Windows specifications).
A displayed image enlarged with 1:1 magnification, such as loupe, does not produce these kinds of problems. In addition, since monochrome images are compressed in the gray scale and displayed on the dviout side without relying on Windows, the lines may not disappear even if reduced.
Set -gfit: to ON.