# Image Compressor

> An image compressor re-encodes a photo at a lower quality setting to cut its file size, usually by 60-80% with no visible difference at 80% quality. Compression happens on a canvas in your browser and the original file is never uploaded.

Source: https://rankcert.com/tools/image-compressor
Free, no signup. Updated: 2026-08-29

## How to use it

1. Choose an image or drop it in.
2. Move the quality slider and watch the file size change in real time.
3. Stop at the point where you can first see a difference, then step back one notch.

## Questions

### What quality setting should I use?

80% is the usual sweet spot for photographs - typically a 60 to 80% size reduction with no visible difference. Below 60% compression artefacts start showing on gradients and skin tones.

### Is this lossless?

No. It re-encodes as JPEG, which is lossy by definition. That is what makes the saving large. For lossless compression you want a PNG optimiser instead.

### Why did my PNG get bigger?

PNGs with few colours are already efficiently compressed, and re-encoding a screenshot as JPEG can grow it. For flat-colour images, convert to WebP instead.

### How small should a web image be?

Under 200KB for a hero, under 100KB for anything else. Google flags images over roughly 500KB as a Core Web Vitals problem, and they are usually the cause of a slow LCP.

### How small should a web image be?

Under 200KB for a hero and under 100KB for everything else. Google's Lighthouse flags images that could save more than 4KB, which in practice means most unoptimised photos.

### What is the difference between lossy and lossless compression?

Lossy discards detail the eye is unlikely to notice and cannot be undone. Lossless rearranges the data so it reconstructs exactly, and saves far less. JPEG and WebP are lossy; PNG is lossless.

### Why did compressing my screenshot make it worse?

Screenshots are flat colour and sharp text, which JPEG handles badly - it produces ringing around the edges. Keep screenshots as PNG or lossless WebP.

### Does compressing images help SEO?

Indirectly and reliably. Images are the largest asset on most pages, so they usually determine Largest Contentful Paint, which is a ranking signal.

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