Optimizing Asset Management for Jekyll Sites

Why Asset Management Matters for Jekyll

When building static sites with Jekyll, managing your assets efficiently plays a crucial role in site performance and user experience. Proper handling of CSS, JavaScript, and images reduces load times and bandwidth usage, which is especially important for GitHub Pages hosting with its limited bandwidth and build constraints.

Common Asset Challenges

• Bloated CSS and JavaScript files slowing down pages
• Unoptimized images increasing page size
• Lack of caching leading to repeated downloads
• Difficulty maintaining assets across multiple pages

Organizing Your Assets Folder

Start by establishing a clear folder structure under your Jekyll assets/ directory:

assets/
  css/
    main.scss
    vendor/
      bootstrap.css
  js/
    main.js
    vendor/
      jquery.js
  images/
    logos/
    backgrounds/
    blog/

This structure helps separate custom code from third-party libraries and categorizes images by use case.

Using SCSS for CSS Management

Jekyll supports SCSS preprocessing out of the box. Benefits include:

• Modular CSS files with @import
• Variables for consistent colors and spacing
• Mixins for reusable CSS snippets

Example main.scss:

// assets/css/main.scss
---
---

@import "vendor/bootstrap";
@import "base";
@import "layout";
@import "components/buttons";

This keeps stylesheets organized and easier to maintain.

JavaScript Management Tips

• Load vendor libraries via CDN when possible to leverage caching
• Keep custom scripts modular and organized
• Defer non-critical JS to speed up initial page rendering
• Minify JS files to reduce size

Example of deferring a script:

<script src="/assets/js/main.js" defer></script>

Image Optimization Strategies

Images often make up the largest portion of page size. Use these approaches:

• Compress images without quality loss using tools like ImageOptim or online compressors
• Serve modern formats like WebP where supported
• Use responsive images with srcset for different device sizes
• Lazy-load images below the fold with native loading="lazy" attribute

Example of responsive image markup

<img 
  src="/assets/images/blog/post-image.jpg" 
  srcset="/assets/images/blog/post-image-480.jpg 480w,
          /assets/images/blog/post-image-800.jpg 800w"
  sizes="(max-width: 600px) 480px, 800px"
  alt="Blog post image"
  loading="lazy">

Cache Control and CDN Usage

While GitHub Pages doesn’t support custom cache headers, you can:

• Use fingerprinting (content hashing) in filenames to enable long cache lifetimes
• Host assets on external CDNs like Cloudflare or jsDelivr
• Leverage browser cache by setting appropriate HTTP headers on custom domains or via proxies

Fingerprinting Assets in Jekyll

Fingerprinting appends a hash to filenames to uniquely identify versions:

main-3f1a2c.css

Use plugins like jekyll-assets or scripts during build to automate this. This ensures users get updated files without stale caching.

Automating Asset Builds

Consider integrating build tools such as Gulp, Webpack, or Parcel to:

• Compile SCSS and minify CSS
• Bundle and minify JavaScript
• Optimize images
• Generate hashed filenames

You can run these tools locally or in CI pipelines before pushing to GitHub.

Case Study: Improving Load Time on a Jekyll Blog

A client site had slow load times due to uncompressed images and large CSS files. We:

• Reorganized CSS into modular SCSS files
• Used ImageOptim to reduce image sizes by 40%
• Deployed scripts with defer to improve first paint
• Moved vendor libraries to CDN

Results included a 50% reduction in page load time and improved SEO scores.

Summary

Managing your assets efficiently in Jekyll improves site speed, SEO, and user satisfaction. Adopt a clear folder structure, optimize images, use SCSS, defer scripts, and consider fingerprinting to keep your site performant.

Next up

In the following article, we will cover advanced caching strategies and browser storage techniques for Jekyll sites on GitHub Pages.