PaintZ itself does not collect or store any personal information. PaintZ uses Google Analytics to track visits, which collects anonymous data on how users access PaintZ (e.g., browsers and device types). You can review Google's list of the data reported in the Google Analytics default configuration. You can also use the Google Analytics opt-out browser add-on to prevent Google Analytics from sharing any information.
When you open an image with PaintZ, your web browser may treat it as a “file upload”, but an “upload” into PaintZ still happens entirely on your device. All PaintZ image processing happens on your device, and the file you save (which your web browser may treat as a “file download”) is generated on your device. PaintZ never sends the file over the Internet or stores it in the “cloud”.
If your web browser supports it, PaintZ will request access to your clipboard if you attempt to copy/paste selections. This access is only used to copy/paste image data from/to PaintZ, which is only done when you click a copy/cut/paste button (or use a corresponding keyboard command).
The source code to PaintZ is open to view on GitHub if you wish to verify or help improve it.
PaintZ only has control over itself. Despite the above, PaintZ cannot control or be responsible for what you, your web browser, your operating system, or other software on your computer do with it. If you are privacy-conscious, it is encouraged you also take appropriate precautions at the web browser and operating system levels, and exercise appropriate caution when working online.