How to Compress an Image Without Losing Too Much Quality
By Akmal Ali · Published · Updated · 4 min read
Resize the image to the size it will be shown at, save photos as JPG or WebP and graphics as PNG, and use a quality of 75–85%. That combination usually turns a 4 MB phone photo into a file of a few hundred KB that looks the same on screen.
Every image you compress loses some data. The goal is to lose only data nobody notices. With the right settings, a 3.7 MB phone photo can become a 548 KB file that looks the same on screen.
What the quality setting alone does: a measured ladder
We saved a 12-megapixel photo taken on an iPhone 14 (4032 × 3024 pixels, 3.7 MB) again as JPG at nine quality levels in Chrome, at full size, with the same encoder the tools use:
| Quality | File size | Compared with the 3.7 MB original |
|---|---|---|
| 95% | 4.0 MB | 8% larger |
| 90% | 3.15 MB | 15% smaller |
| 85% | 2.37 MB | 36% smaller |
| 80% | 2.0 MB | 46% smaller |
| 75% | 1.78 MB | 52% smaller |
| 70% | 1.61 MB | 56% smaller |
| 60% | 1.33 MB | 64% smaller |
| 50% | 1.16 MB | 69% smaller |
| 40% | 0.99 MB | 73% smaller |
Two things stand out. At 95% the file got bigger than the original, because the phone had already saved it at a high quality. And the savings flatten out: 95% to 80% halved the file, while 80% to 40%, where the picture visibly degrades, saved only half as much again. Even at 40%, the full-size photo was still about 1 MB. Resizing it to 1600 × 1200 at 90% brought it down to 548 KB. That’s why the steps below start with the dimensions.
1. Resize before you compress
The biggest saving usually comes from dimensions, not quality. A modern phone takes photos of about 4000 × 3000 pixels, but a website or email rarely displays them wider than 1200–1920 pixels. Halving the width and height leaves a quarter of the pixels, and usually removes most of the file size, with no visible loss at the size it’s shown.
Use the image resizer to set a width, or set a maximum width directly in the image compressor.
2. Choose the right format
- Photos: JPG or WebP. Both use lossy compression designed for photographs. WebP is usually 25–34% smaller than JPG at the same visual quality, according to Google’s WebP documentation.
- Graphics with text, logos and screenshots: PNG or high-quality WebP. Lossy JPG compression creates blurry halos around sharp edges.
- Transparency: PNG or WebP. JPG can’t store transparent areas.
A photo saved as PNG is often 5–10 times bigger than it needs to be. Converting it with the PNG to JPG converter is often the single biggest improvement.
3. Pick a sensible quality setting
For JPG and WebP, quality is a trade-off. As a rule of thumb:
| Quality | Result |
|---|---|
| 90–95% | Visually identical; for printing and editing |
| 75–85% | Hard to tell apart on screen; best balance for most uses |
| 60–70% | Artefacts start to show in smooth areas when you look closely; fine for thumbnails |
| Below 50% | Visible blocks and smudging, especially in skies and skin |
As the ladder above shows, most of the saving happens between 95% and 80%, which is why the middle of the range is the sweet spot.
Image Compressor
Auto mode, a quality you choose or a target size, with a before-and-after comparison and up to 20 images at once.
4. Don’t compress the same image repeatedly
Each time a JPG is opened, edited and saved again, it loses a little more quality. Keep your original file, and always compress from the original rather than from an already-compressed copy.
5. Check the result at the size it will be viewed
Zooming to 400% will reveal compression in any image. What matters is how it looks at its real display size. Open the compressed file next to the original at normal size. If you can’t tell which is which, the compression is fine.
What if you need a specific file size?
Upload forms often set a hard limit. Instead of trying quality levels by hand, use Compress Image to 100KB or Compress Image to 50KB. They search for the highest quality that fits, and reduce dimensions only when necessary. How many pixels survive depends on the image: the busy test photo above kept 615 × 462 pixels in 50 KB, while a 4000 × 3000 test image with flat colours kept 1563 × 1172.
Frequently Asked Questions
Why did my compressed JPG get bigger?
Saving a JPG again at a higher quality than it was made with adds data instead of removing it: our 3.7 MB test photo came out at 4.0 MB at 95%. Use 85% or lower, or let the Image Compressor keep the original when it can’t make it smaller.
Can I compress a photo without losing anything at all?
Only with lossless formats such as PNG, and for photos that usually makes the file bigger, not smaller: the same test photo was 24.5 MB as PNG. For photos, a lossy setting high enough that nobody can see the difference is the practical answer.
Should I compress photos before posting them on social media?
Usually not. The platforms resize and recompress every upload, so give them a good-quality original at their recommended size, and their compression starts from the best copy.