Download & Optimize Hugo images hosted on other websites (e.g. GitHub, imgur, or AWS S3)

README.md

• Confirmed works on Cloudflare pages.
  • Depends on Ruby and wget and imagemagick
• This script uses JPG with quality 85 and interlace -plane (progressive JPEG)
  • Further improvement like WebP may be required

optimize-images.rb

#!/usr/bin/env ruby

IMAGE_REGEX = /(https:\/\/.*\.(?:png|jpg|jpeg))/

`mkdir -p .cache`

Dir.glob('content/post/*.md') do |file|
  puts "===> Start: #{file.to_s}"

  content = File.open(file).read
  content.scan(IMAGE_REGEX) do |image|
    url = image[0]
    puts "===>  Downloading: #{url}"
    `wget -nc -P .cache #{url}`
    png = url.split('/')[-1]
    jpg = png.sub(/(png|jpg|jpeg)$/, 'jpg')
    `convert -quality 85 -interlace Plane .cache/#{png} static/#{jpg}`
    content = content.sub(url, "/#{jpg}")
  end

  File.open(file, 'w') do |f|
    f.puts content
  end

  puts "===> End: #{file.to_s}"
end