Merge branch 'docs-compress-images' into 'master'

Compress uncompressed images

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/145098



Merged-by: Ashraf Khamis <akhamis@gitlab.com>
Approved-by: Ashraf Khamis <akhamis@gitlab.com>
Co-authored-by: Marcel Amirault <mamirault@gitlab.com>