Image Watermark

The watermark is composited onto each image as a separate layer: your text, in white with a thin dark outline so it reads on light and dark areas alike, or a logo you upload. Opacity sets how much of the picture shows through. The mark sits in a corner or the centre, or tiling repeats it across the whole image, which is harder to crop away than a single corner mark. Every image in the batch gets the same treatment. A logo is sized as a share of each image, so it stays proportionate whether the picture is large or small; text is set in pixels, so the same size looks bigger on a small image than on a large one.

Where it stops: A watermark deters casual reuse; it does not prevent it. A corner mark can be cropped off, and any mark can be painted out with enough effort, so treat it as a claim of authorship rather than protection. Heavy tiling across the middle of a photo protects it better and also ruins it as something anyone wants to look at, which is the trade you are making. Metadata is a quieter way to assert authorship and survives cropping. A logo is only ever shrunk to fit, never enlarged, so upload one at least as large as you want it to appear.