How this works, and why nothing is uploaded

Every tool on this site runs inside your own browser. Your file is opened, changed and saved by the phone or computer you are holding, and it is never sent to us or to anyone else.

What actually happens when you add a file

When you choose a file, the browser hands the page a reference to it on your own disk. The page reads those bytes into memory, does the work, and writes a new file back out to your downloads. At no point is there a request carrying your photo to a server, because there is no server to carry it to. This site is a folder of files on a content network: it hands out pages, and it has nowhere to put an uploaded photo even if we wanted one.

Where the work happens

Resizing a twelve megapixel photo is real work, and doing it on the main thread would freeze the page while it ran. So the heavy lifting happens in a Web Worker, which is a second thread inside the same tab. The compression itself is done by the same libraries desktop tools use, compiled to WebAssembly so they run at close to native speed in a browser.

How to check this yourself

You do not have to take our word for it. Two ways to test it:

1. Open any tool, then switch on airplane mode, then use it. It still works. A tool that uploaded your file could not.
2. Open your browser's developer tools, go to the Network tab, and process a file. You will see the page and its code load, and after that nothing carrying your file. No upload request appears, because none is made. On a guide page with an advert at the bottom, you will also see Google's requests from the sealed advert frame. None of them carry your file, because that frame cannot see it.

What we can and cannot see

We cannot see your files, their names, their contents or anything inside them. None of it reaches us.

What we can see is what any website can see: our host records that a page was requested, from roughly which part of the world, and by which kind of browser. That is ordinary web server logging and it happens before any of our code runs. It contains nothing about your file.

What is stored on your device

Your choice of light or dark theme, and a copy of this site's own pages and code. That copy is what lets a tool keep working in airplane mode once you have opened it. It holds our files only: nothing about your files is written to your device or remembered between visits. Close the tab and the file is gone from the page's memory.

The honest limits

Two things worth saying plainly.

First, we cannot promise a portal will accept your file. We can tell you exactly what your file is and exactly what we changed. Whether a particular website is happy with it is that website's decision, and any tool claiming otherwise is guessing.

Second, compression loses detail. That is what makes a file smaller. We always keep the highest quality that fits the limit you set, but a photo squeezed to twenty kilobytes will not look like the original, and nothing can change that.