I have a Jekyll blog with 1,000s of posts. Now I'm planning to use Cloudflare Image Resizing to optimize the website. To make it happen I need to modify the image tag rendered from the markdown files.
In markdown file:
 Rendered image tag:
<img src="images/apple.jpg" alt="Apple"> How I want it to be:
<img src="/cdn-cgi/image/width=80,quality=75/images/apple.jpg" alt="Apple" > Thanks in advance
The very last hook that gets called before writing posts to disk is :posts, :post_render. We can modify output at this hook to make edits to rendered posts and draft posts, regardless of whether they were originally written in Markdown or HTML:
module JekyllPluginHooks Jekyll::Hooks.register(:posts, :post_render) do |post| post.output.gsub!('<img src="images/', '<img src="/cdn-cgi/image/width=80,quality=75/images/') end end Terminology
post includes drafts and blog posts.document includes web pages in all collections, including drafts and blog posts.page is a web page that does not belong to a collection, such as posts or drafts.For Completeness
To modify all web pages in every collection, not just drafts and posts, use the :documents hook instead of the :posts hook in the above code example:
module JekyllPluginHooks Jekyll::Hooks.register(:documents, :post_render) do |document| document.output.gsub!('<img src="images/', '<img src="/cdn-cgi/image/width=80,quality=75/images/') end end To also modify web pages that are not in a collection (for example, /index.html) also write:
module JekyllPluginHooks Jekyll::Hooks.register(:pages, :post_render) do |page| page.output.gsub!('<img src="images/', '<img src="/cdn-cgi/image/width=80,quality=75/images/') end end If we want all web pages to be modified, we can rewrite the above and extract the common code to a new method called modify_output:
module JekyllPluginHooks def modify_output Proc.new do |webpage| webpage.output.gsub! \ '<img src="images/', \ '<img src="/cdn-cgi/image/width=80,quality=75/images/' end end module_function :modify_output Jekyll::Hooks.register(:documents, :post_render, &modify_output) Jekyll::Hooks.register(:pages, :post_render, &modify_output) end References