What is a watermark — mark on a photo
What a photo watermark is: text or logo over an image for copyright and drafts, plus an online tool.
A watermark is a visible mark drawn on a photo: a name, URL, logo or the word Proof. It does not encrypt the file; it makes reuse obvious and points back to the author.
Opacity, size and placement matter. A corner mark is enough for a portfolio. A tiled repeat is better for unreleased work. In ToolsHelper you add the mark locally and download a new file.
A watermark is a visible or faint mark burned into a copy of an image so the copy can be traced or discouraged. It is not a lock. A corner logo is easy to crop; a mark across the subject is harder and also harder to read through. Opacity is a balance: 100% hides the photo, 10% disappears on a busy background. This page defines the mark. Painting one onto your file is the converter.
FAQ
Is a watermark the same as metadata?
No. EXIF is hidden data. A watermark is pixels you can see.
Can it be removed?
A simple corner mark can be cropped. Tiling makes removal harder, not impossible.