How to Compress Images Without Losing Visible Quality
Shrink JPEG, PNG, and WebP files for the web with quality presets that match your use case — featured images, product photos, thumbnails, or email attachments.
More utilities that pair well with this guide:
Why this matters
The home page hero image is 4.2 MB. Lighthouse scores tank. Mobile users on 4G see a blank rectangle for two seconds. Compress to 320 KB at 80% quality and the eye cannot tell the difference, but Time-to-Largest-Contentful-Paint drops by ~1.6 seconds. That 1.6 seconds correlates with a measurable bump in conversion. Image compression is one of the cheapest performance wins on the web, and a privacy-first browser tool means you can do it without uploading customer photos to a SaaS.
Three real scenarios
Drop all 12 in, set 80% quality + WebP, download zip, push to CDN.
LCP under 2s
Resize + compress in one pass; product cards load fast on mobile.
Consistent listings
Compress 25 photos to ~200 KB each; total fits within 25 MB Gmail limit.
Files under email size cap
Walkthrough
Open the Image Compressor.
Drop one or many files
JPEG, PNG, WebP supported. Multi-file mode batches in parallel.
Pick the target format
WebP for web (smallest), JPEG for emails and legacy compatibility, PNG for screenshots/logos with transparency.
Set quality
50 = aggressive (visible artifacts on photos), 75 = good default, 90 = near-lossless. Slide and watch the file size update.
Resize on the way out
Optional: cap longest edge to 1600px or 800px. Most landing-page photos look fine at 1600px.
Download single file or zip
Single file → standard browser download. Multi-file → packaged zip.
Original
hero.jpg — 4,210 KB
3840 × 2160 pxWebP @ 80%
hero.webp — 318 KB (-92%)
3840 × 2160 px (unchanged)
SSIM 0.984 (perceptually identical)
Power tips
- WebP is supported in 95%+ of browsers. Use AVIF for the absolute best compression but only when you need it; AVIF encode is slower and not yet ubiquitous.
- Don't double-compress. Re-saving an already-compressed JPEG at 75% adds artifacts. Always start from the original.
- Strip metadata for public images. EXIF can include GPS coordinates from a phone camera. The compressor strips it by default.
- Compress before resizing for screenshots with sharp text — quality artifacts magnify when scaled up.
Common pitfalls
Common mistake
Output is bigger than input
Either the source was already heavily compressed (re-encode adds overhead), or you set a higher quality than the original. Drop quality below the source's.
Common mistake
Transparency turns into ugly halos
JPEG doesn't support transparency. Save PNGs with alpha as WebP or PNG, not JPEG.
Common mistake
Browser tab freezes on a 100 MB photo
The Web Worker handles large files but each tab has a memory budget. Process 4-5 large files at a time, not the whole album in one drop.
When this is the wrong tool
- Vector assets (SVG, AI) — vectors don't benefit from raster compression. Use SVGO or the SVG to PNG converter for raster targets.
- Lossless archival storage of original photographs — keep a master copy in PNG/RAW and compress exports.
- Programmatic build pipelines —
imagemin,sharp, orvipsfrom a Node/Python script integrates better with CI/CD.
FAQ
Are my images uploaded to a server?
No. Compression runs in your browser using canvas and the WebP encoder built into the browser. Nothing leaves the page.
What's the difference between WebP and AVIF?
AVIF compresses ~30% better than WebP at the same quality but takes ~10x longer to encode. WebP is a good default; AVIF is best for static assets where encode time doesn't matter.
Can I batch resize without compressing?
Yes — set quality to 100 and apply only the resize step.
Next steps
- Convert legacy formats to modern ones with the Image converter.
- Strip personal metadata before sharing with the EXIF editor.
- Add brand watermarks before publishing using the Image watermark tool.