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Quick answer
To compress an image to 100KB, open Zappy Compress Image, add your photo, choose Medium (about 50% smaller) or Extreme (about 80% smaller) and click Compress image. The width and height stay the same, and the new size is shown before you download.
How to compress an image to 100KB in 3 steps
Add your image
Open Compress Image and drop in a JPG, PNG or WebP up to 25 MB.
Pick Medium or Extreme
Start with Medium. If the size shown is still over 100KB, run it again on Extreme.
Download
When it is under 100KB, download the compressed image. The dimensions are unchanged.
Will compression alone get you to 100KB?
Swipe to compare →
| Starting image | Compression alone? | Better approach |
|---|---|---|
| Under about 400KB | Usually, on Medium or Extreme | Compress |
| A 2–5 MB phone photo | Rarely | Resize to about 800 px wide, then compress |
| A large PNG screenshot | Sometimes | Convert to JPG or WebP, then compress |
How to keep it looking good
- Use Medium first. It is often all you need and looks almost identical.
- Crop out empty background before compressing.
- For photos, JPG or WebP compress far better than PNG.
- Check faces and text at 100% zoom before uploading.
Compressing several images for one form
When a form asks for several photos, each under 100KB, compress them one after another with the same level so they match in quality. For a single upload that must hold several images, combine them with JPG to PDF and choose Small enough to email.
PNG, JPG or WebP for a 100KB target?
Swipe to compare →
| Format | At the same dimensions | Use when |
|---|---|---|
| JPG | Small | It is a photo and the form accepts JPG |
| WebP | Smallest | The site accepts WebP |
| PNG | Largest for photos | It is a logo, screenshot or needs transparency |
If a form requires JPG and you have a PNG screenshot or photo, converting it usually brings the size down dramatically before you even compress. Convert to WebP with WebP converter when a website accepts it.
How to check an image's size in KB
- iPhone: in Photos, open the picture and swipe up, or tap the i button, to see its size. In Files, touch and hold and choose Get Info.
- Android: in Google Photos, open the picture and swipe up for details.
- Mac: select the file in Finder and press Command-I.
- Windows: right-click the file and choose Properties.
Zappy shows the new size on screen after resizing or compressing, so you can confirm it before downloading.
Where a 100KB image limit is common
- Application portals asking for a photo at exact pixel sizes.
- Website images that need to load quickly.
- Email signatures and newsletter images.
Frequently asked questions
How do I compress an image to 100KB for free?
Open Zappy Compress Image, add your photo, choose Medium or Extreme and click Compress image. The new size is shown before you download.
Will compressing change my image's dimensions?
No. Compress Image keeps the same width and height and only reduces the file size.
Why is my phone photo still over 100KB?
Phone photos have millions of pixels. Resize it to around 800 pixels wide first, then compress.
Should I use Medium or Extreme to reach 100KB?
Start with Medium. Only use Extreme if the size shown is still over 100KB, since it removes more detail.
Does it work with PNG?
Yes. PNG, JPG and WebP all work, but photos compress far better as JPG or WebP.
Does it work offline?
Yes. Once the page has loaded, compression runs on your device, even in Airplane Mode.
Is my image uploaded?
No. Everything happens in your browser, so the image stays on your device.