Resize a photo, bring it under a KB limit, make a passport photo, or turn scans into one PDF. Everything happens on your own phone or computer. Nothing is uploaded, there is no account, and no watermark is added.
Most tool websites work in a different way. You upload the file, their server changes it, and it comes back to you. For that moment your photo or your document is sitting on a company's computer, and you have to trust what happens to it next.
These tools do not work like that. Your browser reads the file straight from your device, does the work there, and saves the result back. The file never travels. That is also why the tools stay quick even when your connection is slow, and why nothing is stored anywhere afterwards.
No sign-up, no daily limit, no watermark on your result. The adverts on the page pay for the hosting, so the tools themselves stay free. If a tool cannot do what you asked, it tells you plainly instead of pretending it worked.