• Windows 11
• Claws Mail

• X-Face

TL;DR - You can't use X-Face because compface isn't available, and you can't use "Face" because of file size constraints.

• There's also this tool (which didn't help): https://www.dairiki.org/xface/xface.php

• 2023-05-15 - with Claws Mail 4.1.1 on Windows 11 - Failed
• (date not recorded) - with Claws Mail (version not recorded) on Windows (version not recorded) - Failed

• (date not recorded) - with Claws Mail (version not recorded) on Linux (distribution not recorded) - Success, but notes were not taken. I am not sure if, and where, any data might be archived.

[unresolved] - Face ∞

Face

1. Use GIMP to save your image as an .xbm file.

2. Launch Windows Subsystem for Linux 2

3. Use ImageMagick to convert it:

\sudo  \apt-get  update
\sudo  \apt-get  install  imagemagick

file_source="image.xbm"
file_target="image"

# Note that although 48x48 is the maximum supported, there is a serious file size constraint, and so it's best to significantly reduce the size.
\convert  ./"$file_source"  -monochrome  -resize 24x24!  "$file_target".temp.pgm
\convert  "$file_target".temp.pgm  -resize 24x24  -colors 2  -dither FloydSteinberg image "$file_target".face
\rm  --force  "$file_target".temp.pgm

\echo  "Confirm that this file is less than 725 bytes:"
\ls  -l  "$file_target".face

Unfortunately, Claws Mail requires a 48x48 image, and that cannot be generated by the above means. I also cannot create a 24x24 first, and then upscale that to 48x48. Maybe there's a way to do a more lossy conversion?

4. Configure Claws Mail:

1. Open Claws Mail
2. Configuration > Edit accounts
3. Select your account and either double-click or click [Edit]
4. Send
5. Header: [x] Add user-defined header
6. Click [Edit] next to Add user-defined header
7. Header: Face

8. Next to Value, click [Browse]

Fails because it both requires 48x48 and an image of less than 725 bytes.

[Cannot work] - X-Face ∞

X-Face

1. Use GIMP to save your image as an .xbm file.

2. Launch Windows Subsystem for Linux 2

3. Use ImageMagick to convert it to a .xface file:

\sudo  \apt-get  update
\sudo  \apt-get  install  imagemagick

file_source="image.xbm"
file_target="image.xface"

\convert  "$file_source"  -monochrome  -resize 48x48!  "$file_target"

4. Configure Claws Mail:

1. Open Claws Mail
2. Configuration > Edit accounts
3. Select your account and either double-click or click [Edit]
4. Send
5. Header: [x] Add user-defined header
6. Click [Edit] next to Add user-defined header
7. Header: X-Face

8. Next to Value, click [Browse]

Fails because compface doesn't exist/work on Windows. :(