How it works, and why your photo stays private
CompressDrop is a set of web pages with a compression engine that runs inside your browser. There is no server that receives photos. We don't have one.
- On your device. The photo is processed by your own phone or computer.
- Never uploaded. No photo is sent to us or anyone else.
- No accounts. Nothing to sign up for, so there's no personal data to leak.
What happens to your photo
- Your browser opens the photo you choose. It reads it from your phone or computer. Nothing is sent anywhere.
- It crops and resizes it, and adds the name strip or the signature if the tool asks for one.
- A compression engine runs in the background of the page. It's MozJPEG, Mozilla's JPEG encoder, built to run in browsers. It tries several pixel sizes and quality levels and keeps the best file that fits your limit.
- You download the result straight from your browser. When you close the page, the photo and the result are gone.
Check it yourself
You don't have to take our word for it.
The airplane-mode test
- Open CompressDrop and compress any photo once. This loads the engine.
- Turn on airplane mode, or switch off Wi-Fi and mobile data.
- Compress another photo. It still works, because nothing needs the internet. After your first visit, the whole site works offline.
On a computer: the Network tab
Open your browser's developer tools (press F12) and choose the Network tab, then compress a photo. You'll see the site's own files load from compressdrop.in, Cloudflare's visitor-statistics script, and one small report of page-load speed (/cdn-cgi/rum). No request contains your photo.
What else the page loads
Visitor statistics: Cloudflare Web Analytics loads a small script from static.cloudflareinsights.com to count page views and measure how fast pages load, and sends that to our site's /cdn-cgi/rum address. It uses no cookies and doesn't follow you to other sites.
None of them receive your photo. It never leaves the page's memory on your device.
Works offline, and installs like an app
After your first visit, your browser keeps a copy of the site, so the tools keep working without internet. You can also add CompressDrop to your home screen:
- Android: tap Install app at the bottom of any page, or open Chrome's menu and choose Add to Home screen.
- iPhone and iPad: in Safari, tap Share, then Add to Home Screen.
Add CompressDrop to your Home Screen
- In Safari, tap Share.
- Choose Add to Home Screen.
How we count KB
Exam portals don't agree on what a kilobyte is. Some count 1 KB as 1,000 bytes and others as 1,024. A file that one portal accepts as “50 KB” can be rejected by another. So we take the strict reading every time:
- For a maximum, 1 KB = 1,000 bytes, and we stay one byte under.
- For a minimum, 1 KB = 1,024 bytes.
| Your form says | Our file is |
|---|---|
| under 20 KB | at most 19,999 bytes |
| under 50 KB | at most 49,999 bytes |
| under 100 KB | at most 99,999 bytes |
| at least 20 KB | at least 20,480 bytes |
Either way the portal counts, the file passes.
Built on open source
- MozJPEG, Mozilla's JPEG encoder, through the jSquash browser packages (@jsquash/jpeg 1.6.0 and @jsquash/resize 2.1.1, Apache License 2.0). This software is based in part on the work of the Independent JPEG Group.
- Lucide icons (ISC License).
- The site is built with Astro (MIT License).
Security
The site is plain files served over HTTPS. There are no accounts, logins or databases, so there's no personal data for anyone to steal. If you find a security problem, please email hello@compressdrop.in. Our security.txt has the details.