convert utility "improper image header" for SigLib generated BMP

[rjhenson]

ImageMagick version

6.9.13.25-1

Operating system

Linux

Operating system, version and so on

RedHat EL8

Description

$ convert /tmp/topaz/signature-0.bmp /tmp/topaz/signature-0.gif
convert: improper image header `/tmp/topaz/signature-0.bmp' @ error/bmp.c/ReadBMPImage/712

Steps to Reproduce

Using Topaz SigLib version TopazSigLib-2.1-2076.x86_64 (confirmed latest by Topaz support team) to generate a BMP file followed by this system cmd to convert to GIF:

$ convert /tmp/topaz/signature-0.bmp /tmp/topaz/signature-0.gif
convert: improper image header /tmp/topaz/signature-0.bmp' @ error/bmp.c/ReadBMPImage/712. convert: no images defined /tmp/topaz/signature-0.gif' @ error/convert.c/ConvertImageCommand/3234

Also tried this:
$ convert -define bmp:ignore-filesize=true /tmp/topaz/signature-0.bmp /tmp/topaz/signature-0.gif

3 example BMP files are attached were generated with ImageFileFormat options 0, 1 for compressed, color

signatureZIP.zip

resp.

Images

Zip contains signature0.bmp and signature1.bmp

[rjhenson]

NOTE: The convert command was working with the ImageMagick library PRIOR TO 6.8.13.14
Nothing has changed on the SigLib side which generates the BMP since Jul 2023.

[dlemstra]

Our code contains checks for files that are written incorrectly. Your bmp file contains a file size that is invalid. With ImageMagick 7 you can use -define bmp:ignore-filesize=true to ignore that invalid file size. That option was not yet available for ImageMagick 6 and it will become available in the next release.