#placed in .htaccess together with coming-soon.html
<IfModule mod_rewrite.c>
  RewriteEngine On

  # Allow all static image
  RewriteRule ^static/img/(.*)$ static/img/$1 [L]

  # Show coming soon page
  RewriteCond %{REMOTE_ADDR} !=127.0.0.0 #internal public ip address
  RewriteRule ^ coming-soon.html [L]
</IfModule>