How to compress images without losing quality
Big image files slow down websites, fill up your phone and can be too large to email. Compressing an image makes the file smaller. Done right, people won't notice any difference in how it looks.
What does compressing an image actually do?
A photo is made of millions of colored dots (pixels). Image formats like JPG and WebP store those dots in a clever way that throws away details your eyes don't really notice. A higher "quality" setting keeps more detail and makes a bigger file. A lower setting makes a smaller file but can add blur or blocky patches.
The two ways to make an image smaller
- Lower the quality. For most photos, a quality of about 70–80% looks almost the same as the original but can cut the file size a lot.
- Make the image smaller in pixels. A photo from a modern phone can be 4000 pixels wide, but a website or WhatsApp rarely shows more than 1080–1920 pixels. Reducing the width often saves even more than lowering the quality.
Using both together gives the best result.
Which quality should I choose?
| Use | Suggested quality | Suggested max width |
|---|---|---|
| Website photos | 70–80% | 1600–1920 px |
| Email attachments | 70% | 1600 px |
| Social media | 80–85% | 1080–2048 px |
| Print or archive | 90% or keep the original | Full size |
JPG, PNG or WebP?
For photos, JPG and WebP compress much better than PNG. WebP usually makes the smallest files at the same quality and works in all modern browsers. PNG is best for screenshots, logos and images with sharp edges or transparent backgrounds. Read our JPG vs PNG vs WebP guide for more.
How to compress an image with Postora
- Open the Compress tool and choose your image.
- Pick a quality preset or move the slider. The new file size updates as you go.
- Optionally set a maximum width to shrink very large photos.
- Check the result and the size saved, then download it.
Common mistakes
- Compressing the same JPG again and again. Each save loses a little more detail. Always start from the original.
- Using a very low quality for text. Text and sharp lines show blur quickly. Use PNG or a higher quality.
- Expecting PNG to shrink a lot. PNG keeps every detail, so photos saved as PNG stay large. Convert to JPG or WebP instead.
Postora compresses images in your browser. Nothing is uploaded, so it is private and quick, even for large photos.