Image optimization techniques for improving performance
Your loading speed = your rankings and conversions. If unoptimized images are “dragging” your site down, it's time to take action. Below you'll learn how to choose the right formats, implement lazy loading, and use adaptive images.
Why image optimization is important
Images are a frequent cause of long page loads and poor LCP scores. With high search competition and the rise of mobile users, every second counts. The less the user waits, the higher the chance of conversion and loyalty.
Choosing an image format
The format directly affects the file size. Use JPEG for photos, PNG for images with transparency, and WebP/AVIF for maximum compression without noticeable loss of quality. If browser support is not an issue, move to more modern formats.
| Format | Advantages | Disadvantages | Where to use |
|---|---|---|---|
| JPEG | Excellent balance of quality/weight | Loss of quality with heavy compression | Photos |
| PNG | Transparency support | File larger than JPEG | Logos, icons, graphics |
| WebP | Good compression, transparency support | Limited support in older browsers | Photos, graphics, animations |
| AVIF | Even less weight, good detail | Novelty of format, not supported everywhere | Promising choice |
| SVG | Vector graphics, does not lose quality when scaled | Not suitable for photos | Icons, illustrations, logos |
Responsive images: srcset and sizes
Use srcset and sizes to adapt to different screens. This way the browser will decide which version of the image to load on a particular device.
<img
src="example-400w.jpg"
srcset="example-400w.jpg 400w, example-800w.jpg 800w, example-1200w.jpg 1200w"
sizes="(max-width: 600px) 400px, (max-width: 1200px) 800px, 1200px"
alt="Example"
loading="lazy"
/>
Lazy Loading: delayed loading of images
Allows you to load images only when they are in view.
- Saves traffic and speeds up initial loading
- Reduces LCP by focusing on critical content
Example:
<img src="example.webp" alt="Lazy load image" loading="lazy" />
Tools and services for optimization
| Tool | Description | Link |
|---|---|---|
| TinyPNG | Online service for compressing PNGs and JPEGs | TinyPNG |
| ImageOptim | Image Optimization on macOS | ImageOptim |
| Squoosh | A powerful tool from Google | Squoosh |
Practical tips and examples
- Modern formats: move to WebP or AVIF, add fallback if necessary.
- Responsiveness: customize
srcsetandsizesfor different devices. - Lazy Loading: use the
loading=“lazy”attribute and Intersection Observer for dynamics. - Automation: connect build plugins (webpack, etc), run optimization at CI/CD stage.
- Analyze: regularly check Google Lighthouse, PageSpeed Insights and keep an eye on Web Vitals.
Conclusion
Image optimization is the key to a fast and responsive page. Saving on image weight improves UX, increases search engine rankings and has a positive impact on conversions.
"Every kilobyte counts. A fast site = a satisfied user. “
Want to take your project to the next level? Start with image optimization and use our audit service. An expert approach will save time and resources, and both users and search algorithms will feel the result!