gfxboot-themes software package provides tool to test and create graphical boot logos (themes), you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gfxboot-themes
gfxboot-themes is installed in your system.
Make ensure the gfxboot-themes package were installed using the commands given below,
$ sudo dpkg-query -l | grep gfxboot-themes *
You will get with gfxboot-themes package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Miscellaneous |
| Package | gfxboot-themes |
| Version | 4.5.2-1.1-5 |
| Description | tool to test and create graphical boot logos (themes) |
| Sub Section | Miscellaneous |