Image Compressor
Compress images online for free. Reduce JPG, PNG and WebP file size with an adjustable quality slider — no upload, fully private.
Click to choose a file or drag & drop here
JPG, PNG or WebP · compressed privately on your device
Images are the single largest cause of slow web pages, oversized email attachments and rejected upload forms. A photo straight from a phone is routinely 4–8 MB, when the same picture at 300 KB would be indistinguishable on screen.
This compressor re-encodes JPG, PNG and WebP files at a quality level you control, using your browser’s own canvas engine. Nothing is uploaded — the compression happens on your device, so it works with private photos and confidential screenshots.
How to use the Image Compressor
Add your images
Drag them in or click to browse. Several files can be compressed in one batch.
Set the quality level
70%–80% is the sweet spot for photographs: a large size reduction with no visible difference at normal viewing size.
Compare the result
The before and after file sizes are shown along with the percentage saved, so you can judge whether to push the quality lower.
Download
Save individual files, or download the whole batch at once.
What quality level to choose
| Quality | Typical size reduction | Use for |
|---|---|---|
| 90%–100% | 10%–30% | Print, archival, professional photography |
| 75%–85% | 50%–70% | The default for almost everything — web, email, portfolios |
| 60%–75% | 70%–85% | Thumbnails, social media, blog images |
| Below 60% | 85%+ | Only where size matters more than appearance |
Compression artefacts appear first around sharp edges and text, and last in smooth areas like skies and skin. A photograph tolerates aggressive compression far better than a screenshot does.
Lossy and lossless compression
Lossy compression — JPG and lossy WebP — permanently discards detail the eye is least likely to notice, achieving very large reductions. Lossless compression — PNG and lossless WebP — stores the same pixels more efficiently, typically saving only 5%–20% but changing nothing.
The critical point about lossy compression is that it compounds. Every save re-encodes the already-degraded result, so an image opened and saved repeatedly at 80% quality visibly deteriorates. Always compress from the original, never from a compressed copy.
Why compression matters for a website
Google measures Largest Contentful Paint — how long the biggest visible element takes to appear — as a ranking signal, and that element is usually an image. The target is under 2.5 seconds.
The commercial impact is well documented: roughly half of mobile users abandon a page that takes longer than three seconds, and studies at major retailers have repeatedly found that each additional second of load time measurably reduces conversion. Compressing images is the cheapest performance improvement available on almost any site.
Compress or resize?
These solve different problems and are often confused. Compression keeps the pixel dimensions and reduces the data per pixel. Resizing reduces the pixel dimensions themselves.
For most oversized images, resizing is the bigger win. A 4000-pixel-wide photo displayed in an 800-pixel column is carrying 25 times more data than the screen can use. Resize to the display size first with the image resizer, then compress — in that order the saving is dramatic.
Target sizes worth aiming for
| Use | Dimensions | Target file size |
|---|---|---|
| Full-width hero image | 1920 px wide | Under 200 KB |
| Blog body image | 800–1200 px wide | Under 100 KB |
| Product thumbnail | 400 px wide | Under 30 KB |
| Email attachment | As needed | Under 1 MB per image |
| Profile photo | 400 × 400 px | Under 50 KB |
Frequently asked questions
Does compressing reduce image quality?
Lossy compression discards some detail by definition, but at 75%–85% quality the difference is invisible at normal viewing size while the file is typically 50%–70% smaller. Push lower only when size matters more than appearance.
Are my images uploaded to a server?
No. Compression uses your browser’s canvas engine locally. Your images never leave your device, so private photos and confidential screenshots are safe.
What quality should I use?
Start at 80%. For photographs on the web, 70%–80% is the standard sweet spot. Screenshots and images containing text need higher settings, or PNG instead.
Can I compress several images at once?
Yes. Add multiple files and they are processed as a batch, with a combined download.
Why did my PNG barely shrink?
PNG is lossless, so there is limited room to save. If the image is a photograph, converting it to JPG or WebP with the image converter will reduce it far more.
Will compressing twice make it smaller still?
Slightly, but it damages the image — each lossy save re-encodes already-degraded data. Always start from the original file.
Does compression remove EXIF data?
Yes. Re-encoding through the canvas discards metadata including GPS coordinates, camera model and timestamps — a useful privacy side effect before sharing photos publicly.
What is the best format for the web?
WebP, in most cases — typically 25%–35% smaller than JPG at equivalent quality, and supported by every current browser. Use the image converter to switch.
100% private. Files are processed on your device and never uploaded.
Instant results. No upload queue. Processing time depends on your device.
Free forever. No signup, no watermark, no paid tier.
Works everywhere. Use a modern browser on your phone or computer.
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Image Compressor is one of all the free tools on ToolNest. No account or subscription needed — anywhere in the world.