How to compress images without wrecking the quality
Big images slow down websites, blow past email limits, and eat storage. The good news: most images can be made dramatically smaller with almost no visible difference — if you compress them the right way.
Lossy vs. lossless
- Lossy compression (JPG, lossy WebP) removes detail your eye barely registers. It achieves huge size reductions and is ideal for photos.
- Lossless compression (PNG, lossless WebP) shrinks the file without discarding any pixels — smaller, but not as small as lossy.
The three levers of file size
- Dimensions. A 6000×4000 photo displayed in a 1200-pixel column is carrying four times more pixels than it needs. Resizing to the display size is often the single biggest win.
- Quality setting. Dropping JPG/WebP quality from 100 to around 80 typically cuts size by half with no visible loss.
- Format. Converting to WebP usually saves another 25–35% over JPG or PNG.
A practical recipe
- Resize to the largest size the image will actually be displayed at.
- Compress at ~80% quality (or convert to WebP).
- Check it looks fine at full size; nudge quality up if you see artifacts.
How small to aim for
For web images, under ~200 KB is a good target for most photos; hero images can go a bit higher. For email, keep the whole message under ~10 MB. And as always, browser-based compression means your images are never uploaded to a stranger's server.