Images: remove 3 unused, scale down 1 oversized

Unused: no page, config or other docs repo references the file name. They
were still copied into every deploy.
Oversized: photos and renders over 1 MB and wider than 2400 px are scaled to
2400 px on the long side (same name and format, EXIF and colour profile
kept). Pages show them at 500-1000 px, so nothing visible is lost and the
pages load much faster. The originals stay in git history.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: PCrnjak