Image Compressor
A typical DSLR JPG is 6-10 MB and a phone portrait often breaks 4 MB; most webpages, emails and messaging apps expect much less. This compressor rewrites JPG with mozjpeg, PNG with Oxipng and WebP with cwebp, shrinking file size by 40-80% without the “now it looks awful” moment, and does it locally in your browser so the pictures never leave your machine.
How to compress an image
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1
Drop one or more images
JPG, PNG, WebP; batches of up to 50 files.
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2
Pick a target
Quality slider, target file size in KB, or "web safe" preset.
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3
Review the preview
Before/after side by side so you can see whether the artefacts are acceptable.
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4
Download the optimised files
Individually or as a zip; original names preserved.
How compression works by format
Each format has different levers. Applying the right one is often worth a 2x saving on top of what a generic tool offers.
Format comparison
| Format | Lossy | Alpha | Strength | Typical web compression level |
|---|---|---|---|---|
| JPG | Yes | No | Photos, 8-bit colour | Quality 75-85 |
| PNG | No | Yes | Logos, screenshots, transparent images | Oxipng level 4 |
| WebP lossy | Yes | Yes | Best replacement for JPG, ~30% smaller | Quality 80 |
| WebP lossless | No | Yes | Replaces PNG; often ~25% smaller | Method 6 |
| AVIF | Yes | Yes | Best ratio, slow to encode | Quality 50 equivalent |
Quality targets
- Hero images: JPG quality 85, WebP 82 — retains detail for full-screen display.
- Body images: JPG quality 75, WebP 72 — fine for 800-1200 px wide content.
- Thumbnails: JPG quality 65, WebP 60 — compressing hard is fine at 200 px.
PNG specifics
PNG compression is lossless — quality is not a trade-off, but size reduction depends on colour depth and the compression method. Oxipng level 4 typically shaves 10-30% off a “save for web” PNG from Photoshop.
For screenshots with a small palette (< 256 colours), switching to indexed PNG-8 can halve the file size with no visible difference.
WebP adoption
WebP is supported by every modern browser (Safari 14+, Chrome 32+, Firefox 65+, Edge 18+). Serve WebP with a <picture> element that falls back to JPG for unexpected user agents.
Privacy
The compressors run entirely in your browser using WebAssembly. No file upload, no server-side processing, no logs.
Frequently Asked Questions
For web delivery, yes — WebP at quality 80 is typically 25-35% smaller than an equivalent-looking JPG at quality 85. For email attachments or client hand-off, stick with JPG for universal compatibility.
PNG is already lossless, so savings come from re-indexing the palette and re-running deflate with better strategies. Oxipng at level 4 typically saves 10-30% off a Photoshop export but cannot match the reductions you get from a lossy format like WebP.
Yes. Choose “target KB” mode and the tool iterates quality settings until the output is at or below your target, reporting the effective quality used.
EXIF, XMP and IPTC metadata are optionally retained. For web delivery, stripping is the default because it saves a few KB and removes GPS coordinates that you may not want public.