How to compress an image (JPG, PNG, WebP) with no visible loss

A smartphone photo commonly weighs 3 to 8 MB today. That is perfect for a print, much less so for a website that loads slowly, a form that rejects files over 2 MB, or an email with twenty site photos. Compressing an image often cuts its size by three to ten times with no visible difference on screen.

This guide explains how image compression works, which settings to choose for each use, and how to compress your photos online while keeping control over the result.

How image compression works

Two levers make an image lighter:

1. Encoding quality (for JPG and WebP): the image is recompressed by discarding barely perceptible details. Between 100% and 80%, the difference is usually invisible, while the file size drops sharply.
2. Dimensions: a 4,000 × 3,000 pixel photo contains 12 million pixels. A computer screen rarely shows more than 2 million for one image. Reducing dimensions is often the biggest saving.

Compress an image, step by step

1. Open Compress an image.
2. Drop one or more JPG, PNG or WebP images (up to 20 files, 100 MB in total).
3. Set the Quality with the slider (80% by default).
4. Choose the Output format: JPG, WebP or PNG.
5. Click Process images, compare the Original and the Result, then click Download.

The tool is free, up to 5 files per day, and everything happens in your browser: your photos are not uploaded to our servers.

Good to know: if a recompressed image would end up heavier than the original (it happens with JPGs that are already well optimised), the original is kept, and the tool tells you so.

Which quality setting should you choose?

Use	Suggested quality	Format
Website, blog, online shop	70 to 80%	WebP or JPG
Email, messaging	70 to 80%	JPG
Form with a strict limit	60 to 70%	JPG
Printing, archiving	90% and above	JPG
Logo, screenshot with text	—	PNG

Start at 80%, compare the result with the original by zooming into a detail (a face, text, edges), and go lower if the file is still too heavy.

Which output format?

• JPG: the most compatible, ideal for photos.
• WebP: usually lighter than JPG at equal quality, and it supports transparency. Well supported by recent browsers, a little less by some older software.
• PNG: lossless, with no quality setting; it keeps every pixel, so it barely shrinks a photo. Keep it for logos and screenshots.

Note: JPG replaces transparency with white, while PNG and WebP keep it.

Resize to go further

If your image is still too heavy, reduce its dimensions with Resize an image: choose a longest side of 1,280, 1,920, 2,560 or 3,840 pixels, and the aspect ratio is kept. For a website, 1,920 pixels wide is enough for a full-width image, and 1,280 pixels for an image inside an article.

Good habits

• Keep the originals: strong compression cannot be undone.
• Compress before making a PDF: lighter photos give a lighter PDF with JPG to PDF.
• Check important details (text in a photographed document, faces) before sending.
• For a website, combine sensible dimensions with 75 to 80% quality: it is often the key to a fast site.

Frequently asked questions

Does compressing an image reduce quality?

With JPG and WebP, yes, a little, but at 80% the difference is usually invisible on screen. PNG loses nothing.

Why is my photo barely any lighter?

It was already well compressed. Reduce its dimensions instead, or lower the quality.

How many images can I compress at once?

Up to 20 files and 100 MB in total per batch. The free allowance is 5 files per day across all free tools.

Are my photos uploaded to the internet?

Not for processing, which happens in your browser. Only the allowance count goes through our servers, without the image content.

Can I compress an iPhone HEIC photo?

Convert it to JPG first with HEIC to JPG, then compress the resulting JPG.