Quick answer: Compressing an image makes the file smaller by storing it more efficiently, usually by reducing detail you cannot easily see. Around 70 to 80% JPEG quality and a width that matches how large the picture is shown gives the biggest saving for photos. This tool works in your browser, so your images are never uploaded.
Large images slow down websites, fill up email attachments and hit upload limits on forms and job portals. Compressing them makes the file much smaller while looking almost the same. Most online compressors upload your pictures to a server. This one does the work inside your browser, so your photos never leave your device.
Drop in one image or many, adjust the quality, and see the before and after size for each file straight away. You can also limit the width, which is the biggest single way to cut file size for large phone photos.
Getting the best result
- Quality slider. Around 70 to 80% is a good balance for photos. Lower values make smaller files and show more blocky artifacts.
- Limit the width. A phone photo can be 4000 pixels wide, while a website rarely shows one wider than 1920. Choosing 1920 or 1600 often saves more than the quality slider.
- JPEG or WebP. JPEG works everywhere. WebP is usually smaller at the same quality, and is supported by all modern browsers and most apps.
- PNG files. PNG is lossless, so the quality slider does not change it. For photos, saving as JPEG or WebP gives a far smaller file. Keep PNG for logos, screenshots with text and graphics that need transparency.
Transparent areas become white when saving as JPEG, because JPEG cannot store transparency. Compression is lossy, so keep the original if you may need the full quality later. Very large pictures (above about 16 megapixels) are scaled down to fit the limits of browsers on phones.
A worked example
Example. A 4 MB photo from a phone, saved as a JPEG at 75% quality and limited to 1920 pixels wide, is often around 300 to 600 KB, with no visible loss at normal viewing size. The exact size depends on the picture, so try a few settings and compare the result shown for each file.
Suggested settings by use
| Use | Suggested width | Suggested quality |
|---|---|---|
| Full-width website banner | 1920 to 2560 px | 70 to 80% |
| Picture inside a blog post | 1200 to 1600 px | 70 to 80% |
| Product or gallery thumbnail | 400 to 800 px | 70 to 80% |
| Profile photo | 256 to 512 px | 80 to 90% |
| Photo sent by email or chat | 1024 to 1600 px | 60 to 75% |
Starting points, not rules. Compare the result with the original at the size it will be viewed.
| Format | Best for | Transparency | Compression |
|---|---|---|---|
| JPEG | Photographs | No | Lossy |
| PNG | Logos, screenshots, graphics | Yes | Lossless |
| WebP | Photos and graphics on the web | Yes | Lossy or lossless |
JPEG works everywhere. WebP is usually smaller and is supported by all current major browsers.
Common mistakes to avoid
- Compressing a PNG and expecting a big saving. PNG is lossless, so for photos convert to JPEG or WebP, and keep PNG for logos and screenshots.
- Leaving images far larger than they are shown. A 4000 px photo displayed 800 px wide wastes most of its bytes, so limit the width first.
- Compressing the same file again and again. Each lossy pass loses quality, so always compress from the original.
Go deeper: read our guide How to Compress Images for Your Website.
Frequently asked questions
Are my images uploaded to a server?
No. The compression happens in your browser using your own device, and your pictures are never sent anywhere. You can even use the tool with your connection switched off once the page has loaded.
Why is my compressed file not smaller?
The file may already be well optimized, or it is a PNG, which does not shrink with the quality slider. Try saving as JPEG or WebP, lower the quality, or limit the width.
What quality setting should I use?
For photos on websites, 70 to 80% is a common choice. For quick sharing over chat or email, 60 to 70% is often fine. Compare the result to the original by eye.
How many images can I do at once?
Up to 30 at a time. Each one gets its own download button.
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Sources and further reading
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