Are online image tools safe to use?
It depends entirely on whether the tool uploads your file. Most online editors send your image to a server, where it is processed and stored for some retention window. Tools that run in the browser never transmit the file at all, which removes the question. If a site does not state which it is, assume it uploads.
How to tell which kind you are using
Open the browser developer tools, go to the Network tab, and process an image. If you see a large upload request, the file left your device. If the only traffic is the page itself, the work happened locally.
A faster tell: if a large file is ready instantly with no progress bar, it was almost certainly processed locally. Upload-based tools cannot avoid the transfer time.
What the risk actually is
For a holiday photo, very little. For an invoice, a contract, a medical scan, a payslip or anything with personal data, the file sitting on a third party’s storage is a genuine exposure — and privacy policies commonly reserve the right to retain uploads for a period, or to use them for service improvement.
The deletion promise is also hard to verify. Once a file has been transmitted you are trusting a policy, not a mechanism.
The browser-side alternative
Modern browsers can decode, edit and re-encode images entirely in local memory through the Canvas API. There is no upload, no queue, no file-size cap beyond your own machine, and nothing to delete afterwards. Every free tool on this site works this way, which is also why they are instant.
The one unavoidable exception is AI editing: a model has to see the pixels to redraw them. Even then, only the small area you select needs to be sent — never the whole image.