Merge branch 'compress-images' into 'master'

Docs maintenance: Compress images

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/159047



Merged-by: Lorena Ciutacu <lciutacu@gitlab.com>
Approved-by: Lorena Ciutacu <lciutacu@gitlab.com>
Co-authored-by: Ashraf Khamis <akhamis@gitlab.com>