I need to save an image as Windows Bitmap BMP A1R5G5B5 16bpp.
Source files are 32bpp image files (PNG and/or Windows Bitmap).

Preview saves bmp images at 32 bits per pixel (bpp).

XnConvert saves bmp images at 24bpp.

Imagemagick, Acorn, GraphicConverter do not support saving images at 16bpp.

Photoshop can do it, but I don't own it.

Any ideas?

GUI or command line is fine for me.

  • Not in front of a Mac at the moment, but I wonder if there's a way to do this natively using Quartz Filters?
    – Monomeeth
    Dec 17, 2018 at 21:50
  • Not as far as I could see. Filters don't seem suited to changing the order and weight of bytes in the BMP file format. Dec 18, 2018 at 11:19

1 Answer 1


GIMP has the A1R5G5B5 option when using Export Image as BMP > Advanced Options

A1R5G5B5 in GIMP

For images without any transparency A1R5G5B5 will be greyed out.
Use X1R5G5B5, also 16bpp format, for images without transparency.

X1R5G5B5 in GIMP

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