---
title: "Image is much larger than its rendered size (perf/image-oversized)"
description: "perf/image-oversized: Downloading a 2400px image to display at 300px wastes bytes, memory and decode time."
canonical: https://void-design.vercel.app/rules/perf/image-oversized
lastModified: 2026-09-16
---

# Image is much larger than its rendered size

`perf/image-oversized` · severity **warn** · category Performance · detected by `void perf` and `void audit`

## Why it matters

Downloading a 2400px image to display at 300px wastes bytes, memory and decode time.

## How to fix it

Serve responsive sizes with srcset + an accurate sizes attribute, or let your image CDN / next/image resize.

## Example

```
<img src="/p-800.avif" srcset="/p-400.avif 400w, /p-800.avif 800w" sizes="(min-width: 768px) 50vw, 100vw" alt="…">
```

## References

- https://web.dev/articles/serve-responsive-images

## More performance rules

`void perf` reports 25 rules in this category. Core Web Vitals and bytes: LCP, CLS, TBT, TTFB, JavaScript, CSS, fonts, images, caching and compression, measured as the median of several runs on a throttled mobile and a desktop profile.

- `too-many-requests` Page makes many requests — [perf/too-many-requests](https://void-design.vercel.app/rules/perf/too-many-requests)
- `lcp-image-lazy` LCP image is lazy-loaded — [perf/lcp-image-lazy](https://void-design.vercel.app/rules/perf/lcp-image-lazy)
- `lcp-image-no-priority` LCP image has no fetchpriority="high" — [perf/lcp-image-no-priority](https://void-design.vercel.app/rules/perf/lcp-image-no-priority)
- `lcp-background-image` LCP element is a CSS background image — [perf/lcp-background-image](https://void-design.vercel.app/rules/perf/lcp-background-image)
- `image-legacy-format` Image served in a legacy format — [perf/image-legacy-format](https://void-design.vercel.app/rules/perf/image-legacy-format)
- `images-missing-dimensions` Images without width/height or aspect-ratio — [perf/images-missing-dimensions](https://void-design.vercel.app/rules/perf/images-missing-dimensions)
- `render-blocking` Render-blocking resources delay first paint — [perf/render-blocking](https://void-design.vercel.app/rules/perf/render-blocking)
- `no-text-compression` Text resources are served uncompressed — [perf/no-text-compression](https://void-design.vercel.app/rules/perf/no-text-compression)

Detected by `void perf` and `void audit`. Explain it in a terminal: `void rules perf/image-oversized`