Optimizing Images with Astro

Images often account for the largest portion of a webpage’s size. By properly optimizing them, you can significantly improve your blog’s performance, load times, and user experience.

Why Optimize Images?

• Faster load times: Smaller images mean faster page loads
• Better Core Web Vitals: Improved LCP (Largest Contentful Paint)
• Lower bandwidth usage: Save users’ data
• Better SEO: Speed is a ranking factor for search engines

Modern Image Formats

Traditional formats like JPEG and PNG have served us well, but newer formats provide better compression:

Format	Advantage	Size Reduction	Browser Support
WebP	Good compression, transparency	25-34% smaller than JPEG	95%+
AVIF	Excellent compression	Up to 50% smaller than JPEG	70%+

How Our Blog Handles Image Optimization

This blog automatically optimizes images using Astro’s built-in image optimization.

Using the OptimizedImage Component

You can easily use the OptimizedImage component in your Astro and MDX files:

<OptimizedImage
  src="/path/to/image.jpg"
  alt="Description of image"
  width={800}
  height={600}
  format="webp"
/>

Optimizing Images in Markdown Content

When writing blog posts in MDX, you can combine the flexibility of Markdown with the power of optimized images:

Standard Markdown Image

![Example description](/blog-placeholder-3.jpg)

This will render as a standard image, but you won’t get the optimization benefits.

Using the Component for Better Optimization

For better optimization, you can use the OptimizedImage component:

<OptimizedImage
  src="/blog-placeholder-3.jpg"
  alt="Optimized example"
  width={400}
  height={300}
  format="webp"
/>

How It Works Behind the Scenes

1. The OptimizedImage component uses getImage() from Astro’s built-in image services
2. Images are processed with Sharp, a high-performance image processing library
3. The most optimal format is served based on browser support
4. Original images are preserved as fallbacks for older browsers

Batch Converting Your Images

We’ve also created a utility script to batch convert your existing images to modern formats:

npm run optimize-images

This script:

• Scans the /public directory for images
• Converts them to WebP and AVIF formats
• Preserves the originals for backward compatibility
• Saves the optimized versions to the assets directory

Next Steps

Now that you understand how image optimization works on this blog, try:

1. Using the OptimizedImage component in your next blog post
2. Running the optimization script on your existing images
3. Checking the performance improvements in tools like Lighthouse

By implementing these optimizations, your blog will load faster and provide a better experience for your readers.