The pngquant tool was used https://pngquant.org, and particularly, the
following command:

        /usr/bin/pngquant -f --skip-if-larger --ext .png --speed 1 image.png

Before: 47584K
After : 34924K

Took it from https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/3232

[ci skip]