gajim-urlimagepreview software package provides displays images inside Gajim chat window, 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 gajim-urlimagepreview
gajim-urlimagepreview is installed in your system.
Make ensure the gajim-urlimagepreview package were installed using the commands given below,
$ sudo dpkg-query -l | grep gajim-urlimagepreview *
You will get with gajim-urlimagepreview package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | gajim-urlimagepreview |
| Version | 0.9.8-1 |
| Description | displays images inside Gajim chat window |
| Sub Section | Net |