You posted a photo and it showed up somewhere else without credit. A watermark will not stop a determined thief, but it raises the cost, preserves your claim, and stops casual copying. Type your name or handle, choose a style, and download — all on your own device.
Watermark styles that work
Corner stamp: bottom-right, 50–70% opacity — visible but tasteful. Tiled: repeats across the whole image at 20–30% opacity — the strongest deterrent, because cropping cannot remove it; ideal for previews and sample shots. Centered: 40% opacity for posters and key art. Font size around 2–4% of the image width reads well.
What a watermark can and cannot do
A watermark is a deterrent and evidence, not DRM: a skilled editor can remove simple ones. For valuable work, also keep originals, publish the watermarked version only, and use platform-level protections. And a legal note: adding a watermark does not transfer ownership — only watermark images that are yours.