React websites rely on Vite, Webpack, or other bundlers for asset management, but image optimisation still largely falls to the developer. Poorly optimised images are the most common cause of slow React app performance and poor Core Web Vitals scores. At imgresizr.com, you can optimise images for React websites at the correct format, dimension, and compression — for free.
React Image Optimisation Checklist
| Check | Target |
|---|---|
| Image format | WebP for photos, PNG for transparency |
| Image dimensions | Match display dimensions exactly |
| File size per image | Under 200KB for content images |
| Hero image (LCP) | Under 300KB, preloaded |
| Lazy loading | loading="lazy" on below-fold images |
How to Optimise React Website Images at imgresizr.com
Upload your image to imgresizr.com. Convert to WebP format using the Convert tool — React projects with Vite or Webpack can serve WebP natively in all modern browsers. WebP files are 25–35% smaller than JPEG at equivalent quality. Resize to exact display dimensions using the Resize tool — serving a 3000px image when the container is only 800px wide wastes bandwidth. Create multiple responsive breakpoints: 400px for mobile, 800px for tablet, 1200px for desktop. Use the <img srcset> attribute in React to serve the correct size. Compress all images to under 200KB using the Compress tool — this is the critical step most developers skip.
React Image Performance Tips
- Preload the hero (LCP) image using a link tag in the document head — this is the single biggest LCP improvement
- Use next/image or a similar image optimisation library for automatic format selection and lazy loading
- Add loading="lazy" to all images below the fold — this defers loading until the image is near the viewport
- Use explicit width and height attributes on img tags to prevent layout shift (CLS)
- Run Lighthouse after optimising each batch to measure the impact of your changes
Optimise images for React websites at the correct format and size, free at imgresizr.com.