What is the difference between a windows saved bitmap "PC bitmap, Windows 3.x format" and a gimp saved bitmap "PC bitmap, Windows 95/NT4 and newer format"?

I have need to generate the former through code but there doesn't seem to be any libraries available so it looks like I am going to have to do it the old fashioned way.

  • 1
    When you say "PC bitmap", do you mean an actual .BMP file used in Windows? If so, I'm not sure if or how the format has changed over the years. Perhaps have a look at the Wikipedia page. Also, I think this question may be off-topic, since it's not actually about graphic design. Sorry about that.
    – Billy Kerr
    Oct 17, 2018 at 17:24

2 Answers 2


I don't see these format names anywhere in Gimp.

The Windows bitmap formats are documented here.

As far as I can tell Gimp produces the 40-byte header for R8-G8-B8 images and the 56-byte header for all the other formats (unless the color space information is also saved).

ImageMagick's convert/mogrify tools are likely more suitable than Gimp to convert bitmap formats.


You can create a "PC bitmap, Windows 3.x format" from Gimp by:

  • Making sure your source image uses indexed colour format, not RGB and
  • when exporting to BMP, select "Compatibility Options" in the Dialog and tick "Don't write colour space info".
  • So how does a user look up the color format of the source image in GIMP? Aug 22, 2022 at 19:18
  • To halfway answer your question: I was not using GIMP for looking up the format, but the file util (preinstalled on UNIX/Linux), it gives output like header.bmp: PC bitmap, Windows 3.x format ...
    – bk138
    Aug 23, 2022 at 14:02

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