How to compress images
- Drop one or many images onto the box.
- Set the quality (80 is a good default), optionally a max dimension to also shrink the pixel size, and an output format. Smart picks JPG for photos and screenshots and keeps PNG only where transparency needs it.
- Click Compress. Each image shows its new size and the percentage saved. Download individually or all at once.
Compression runs in your browser — nothing is uploaded, and there are no daily limits or watermarks.
Quality vs size
JPG and WebP are lossy: they discard detail the eye won’t miss, and the quality setting decides how aggressive that is. Typical results for a 12-megapixel phone photo (~4 MB):
| Quality | Size | Visible difference |
|---|---|---|
| 95 | ~2.5 MB | None |
| 85 | ~1.2 MB | None at normal size |
| 75 | ~800 KB | Barely, only zoomed in |
| 60 | ~500 KB | Slight softening |
| 40 | ~300 KB | Noticeable artifacts |
The biggest savings usually come from resolution, not quality. A 4000×3000 photo viewed on a 1920-pixel screen is carrying four times more pixels than can be displayed. Setting max dimension to 1920 typically cuts the size by 70% before any quality loss.
Which format?
- JPG — photos; universally supported.
- WebP — 25–35% smaller than JPG at the same quality, supported by all modern browsers and most apps since 2020. Choose it for websites.
- PNG — logos and anything with transparency. Lossless, so the slider does nothing; use the max-dimension option to shrink it. Most screenshots don’t need PNG — Smart will convert them to JPG at a fraction of the size.
Common uses
- Email attachments — most mail servers cap at 20–25 MB; ten compressed photos fit where three originals didn’t.
- Websites — smaller images load faster and rank better. Aim for under 200 KB per image.
- Forms and portals — upload limits of 1–2 MB are common on government and job sites.
- Messaging — send full-quality-looking photos without the app’s heavy recompression.
- Storage — shrink a photo archive by 60–80% with no visible loss.
Tips
- Compress a copy; keep originals for printing.
- For screenshots with text, use PNG or WebP at high quality — JPG blurs text.
- Re-compressing an already compressed JPG loses a little more each time; go from the original when you can.
- To change size without changing quality, use the image resizer; to change only the format, use the converter.
Frequently asked questions
Will compression make my photos look worse?
At quality 75–85, differences are invisible at normal viewing sizes — that's the range most websites and phones already use. Below 60 you may see softening or blocky areas in gradients. The preview shows the actual output so you can judge before downloading.
Why didn't my PNG get much smaller?
PNG is lossless, so the quality slider doesn't apply, and a browser's PNG encoder is often less efficient than the one that made your file. The Smart setting converts opaque PNGs (like most screenshots) to JPG, which typically cuts the size by 70–90%. If nothing would get smaller, the tool keeps your original rather than making it bigger.
Is there a file-size or file-count limit?
No. Processing is local, so the only limit is your device's memory. Batches of hundreds of photos work on a typical laptop.
Are my images uploaded?
No. Everything happens in your browser's canvas engine. Your images never leave your device, which makes this safe for private photos and documents.
Last updated August 26, 2026.