How to Compress Images Online
- Add your images (JPG, PNG, WebP, GIF or BMP).
- Choose an output format. Smallest keeps JPGs as JPG and turns PNG and WebP into WebP, which is usually the smallest result. Keep format preserves the original file type.
- Set the quality. 70–80% gives big savings with no visible difference for most photos.
- Optionally set a max width. For example, 1920 px for websites. Large phone photos shrink dramatically.
- Click Compress and see how much smaller each file is before downloading.
Why Compress Images?
- Faster websites: images are usually the heaviest part of a page. Smaller images improve loading speed and Google's Core Web Vitals.
- Email and upload limits: get under size limits for email attachments, forms and job portals.
- Save storage: free up space on your phone, laptop or cloud drive.
Recommended Settings
| Use | Quality | Max width |
|---|---|---|
| Website / blog images | 70–80% | 1600–1920 px |
| Email attachments | 70% | 1280 px |
| Social media | 80–85% | 1080–2048 px |
| Printing | 90%+ | No limit |
How Does It Compress PNG?
PNG is lossless, so re-saving a PNG as PNG rarely makes it smaller. The Smallest option converts PNGs to WebP, which keeps transparency and is typically 50–80% smaller. If a compressed file would ever end up larger than your original, K4Converter keeps the original instead, so you never get a bigger file.
Tip: Combine compression with resizing. A 4000 px phone photo resized to 1920 px and saved at 75% quality is often 90% smaller.
Private Image Compression
Unlike most compressors, nothing is uploaded: your images are compressed by your own browser. Need exact dimensions? Use the Image Resizer.
Works on Every Device
The Image Compressor runs in any modern browser: Chrome, Safari, Edge and Firefox on Windows, Mac, Chromebook, iPhone, iPad and Android. Because everything happens on your device, it's fast even on slow connections and keeps working if your internet drops after the page loads. There are no file-size caps set by a server, and no account, email address or watermark is required.
Troubleshooting & Tips
- The file barely got smaller Images that are already optimized can't shrink much. Try a lower quality, the "Smallest" format, or a max width.
- My PNG became a WebP The "Smallest" option converts PNG to WebP for big savings. Choose "Keep format" to keep PNG.
- I see blocky areas Quality is too low for that image. Raise it to 80–85% and compress again.
- Does it remove metadata? Yes. Re-encoding drops most EXIF data such as camera details and GPS location, which also improves privacy.
Frequently Asked Questions
How do I reduce an image's file size?
Add the image above, set quality to around 75% (and optionally a max width), then click Compress.
Will compressing reduce image quality?
At 70–85% quality the difference is usually invisible, while the file becomes much smaller.
How do I compress a PNG?
Choose "Smallest" to convert PNG to WebP, which keeps transparency and is usually far smaller.
What if the compressed image is bigger?
If the result would be larger than the original in the same format, K4Converter keeps your original file.
Are my images uploaded?
No. Compression happens entirely in your browser.
Written by Prakhar Singh, software engineer and creator of K4Converter · Last updated October 2026