-GIF:
This specifies the format of the image file created and used by dviout using Ghostscript. Since it is an integer variable, an integer from 0 to 5 is specified in the parameter file.
0(raw PBM) : For printer output that is not color or only for black-and-white images.
1(monochrome GIF): Not supported by the most recent Ghostscript.
2(monochrome BMP)
3(16 color BMP)
4(256 color BMP): For Previews for both color and black-and-white images.
5(full color BMP): For color Printing using subtle colors.
The above are started with pbmraw, bmpmono, bmp16, bmp256, or bmp16m, respectively, in the -sDEVICE= option in Ghostscript.
Only the settings supported by the Ghostscript being used can be set. (When the "-help" option is added and Ghostscript is started, the supported image formats are determined.)
Note: If BMP for many colors is used to handle color images, the available space in the memory and the hard disk must be large (particularly, as the image gets larger).
Note: When the -sDEVICE=bmp16 option is added and Ghostscript is started, the 16-color BMP format is not used, but only 16 colors in the 256-color BMP format (or something similar) are used.
In this case, even if there is switching between the 16-color mode and the 256-color mode, dviout does not update BMP files and uses them as 16-color BMP.
If 16-color BMP is switched to 256-color BMP, delete the 16-color BMP files, or convert from 16-color BMP -> monochrome BMP -> 256-color BMP.