Lossy compression makes images much smaller by permanently throwing away detail the eye barely notices (JPG and most WebP files work this way), while lossless compression shrinks files without losing a single pixel by storing the same data more efficiently (PNG, and lossless WebP). Use lossy for photos on websites, social media and email, where a 60% to 85% quality setting usually looks the same as the original at a fraction of the size. Use lossless for logos, screenshots, text graphics and anything you will edit again.
- Lossy = smaller files, some detail removed forever. Best for photos.
- Lossless = exact copy, smaller savings. Best for graphics, text and masters.
- Always keep an original. Re-saving a JPG again and again adds damage each time.
- For most web photos, quality around 70 to 80 is the sweet spot.
- Try it on your own photo with the free Image Compressor.
The wedding photo that turned into blocks
Picture a family album being passed around on messaging apps. Someone downloads the wedding photo, crops it, sends it on. Someone else screenshots it, adds a sticker, shares it again. Six forwards later, the bride’s face is a grid of muddy squares and the red sari has strange halos around it.
That is lossy compression stacking up. Each save throws away a little more detail, and the losses never come back. Understanding the difference between lossy and lossless helps you make files small without ending up with the sixth-forward version of your own photos.
How each type works
Formats and their compression
| Format | Compression | Best for |
|---|---|---|
| JPG / JPEG | Lossy | Photos for web, email and social media |
| PNG | Lossless | Logos, screenshots, graphics with text, transparency |
| WebP | Lossy or lossless | Websites: smaller than JPG and PNG at similar quality |
| AVIF | Lossy or lossless | Modern websites wanting the smallest files |
| GIF | Lossless but only 256 colours | Simple animations (often replaced by video or WebP) |
For a full comparison of formats, read JPG vs PNG vs WebP.
What quality setting should you use?
| Use | Suggested JPG quality | Why |
|---|---|---|
| Website photos and blog images | 70 to 80 | Big savings, differences hard to see on screens |
| Hero banners and portfolio images | 80 to 85 | Large images where detail is noticed |
| Email attachments, forms | 60 to 75 | Meeting size limits matters more than fine detail |
| Print or further editing | 90 to 100, or lossless | Keep maximum detail for later |
Signs you compressed too much
- Blocky squares in smooth areas like sky or skin.
- Halos or “mosquito noise” around text and sharp edges.
- Banding: smooth gradients turning into visible stripes.
- Smudged texture in hair, fabric and grass.
If you see these at normal viewing size, raise the quality a little and compress the original again.
A simple workflow
- Keep the originalStore the full-quality file in a folder you never overwrite.
- Resize firstScale the image to the size it will be shown at. Resizing saves more than compression alone. Our cropper can do both.
- Choose the formatPhoto: JPG or WebP. Graphic with text or transparency: PNG or lossless WebP.
- CompressStart around quality 75 in the Image Compressor.
- CompareLook at the result at 100% size, especially faces and text.
Related guides
Learn more in how to reduce image size without losing quality and the ideal image sizes for websites.
Sources
Frequently asked questions
What is the difference between lossy and lossless compression?
Lossy compression permanently removes some image detail to make files much smaller. Lossless compression keeps every pixel and stores the data more efficiently, so savings are smaller.
Is JPG lossy or lossless?
JPG is lossy. Each time you save a JPG with compression, some detail is lost.
Is PNG lossless?
Yes. PNG uses lossless compression, which makes it good for logos, screenshots and graphics with text.
What quality setting should I use for web photos?
A JPG or WebP quality of about 70 to 80 is a good balance for most website photos.
Does compressing a photo many times reduce quality?
Yes, with lossy formats. Always compress from the original instead of re-compressing a compressed copy.
Shrink photos for websites, email and forms in seconds, privately in your browser.
Guides for this tool
Guide · 3 min readHow to Email Large Photos: Make Images Small Enough to Send
Guide · 3 min readHow to Send High-Quality Photos on WhatsApp (HD and Original)
Guide · 3 min readWordPress Image Optimisation: Speed Up Your Website (2026 Guide)
Guide · 3 min readHow to Reduce Image Size Without Losing QualityWant a tool, website or app like this for your business?
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