Install libnetpbm9 by entering the following commands in the terminal:
sudo apt update sudo apt install libnetpbm9
Description:
Shared libraries for netpbm (v9)
This package contains shared libraries used to be used by netpbm. Now we've switched to a single shared library, look out for libnetpbm10. This package is provided for backward compatibility.
Homepage: http://netpbm.alioth.debian.org
Version: 2:10.0-15.3build1
Section: universe/libs