How can I create an image with a transparent background?

[XnTriq]

Next in line: scanned ballpoint pen signature

1. Open EqIcy.jpg in XnView Classic
2. Image → Map → Automatic contrast
3. Image → Map → Posterize… → 16
4. Image → Resize… → 25% / Bilinear
5. Filter → Effects… → Enhance → Enhance Detail
6. Image → 32 bits
7. Filter → Adobe Photoshop Plug-In…
   1. Mac's → Remove White
      MACWHITE.png
   2. Mehdi → Eraser Classic…
      Eraser_Classic.png
   3. Mehdi → Eraser Genuine…
      Eraser_Genuine.png
   4. Mike and Yael → KillWhite…
      KillWhite.png

[XnTriq]

nightsvallow @ deviantArt: Removing a background: Free Tool xnView

Yes, I dragged and dropped the image over an open odt in LibreOffice and it appears to look good

Last but not least: Most word processors (LibreOffice, OpenOffce, Microsoft Office etc.) allow the user to set the transparency in images.

[Elk]

Many thanks for the examples.

I have 32bit versions only. So I obviously had to install a portable XnView 32bit additionally, I assume.

[XnTriq]

I have 32bit versions only. So I obviously had to install a portable XnView 32bit additionally, I assume.

On Windows 10 and XP, KillWhite (KillWhite.8bf), Eraser Classic (eraserclassic.8bf) and Eraser Genuine (erasergenuine.8bf) work with XnView Classic and the 32-bit version of XnView MP.
On Windows XP, Mac's Remove White (MACWHITE.8BF) works with XnView Classic and the 32-bit version of XnView MP, if you have msvcrt10.dll in C:\Windows\ or C:\Windows\System32\.
On Windows 10, Mac's Remove White (currently) doesn't work with any version of XnView.

[Elk]

OK, I have Win 10, thank you very much!