Watermark

The text is drawn straight onto the pixels, so it survives sharing and screenshots. The size is a percentage of the shorter side, which keeps it in proportion on a wide or a tall picture.

About this tool

Put a name, a site or a date onto a picture so it travels with the image. You choose a corner, a size as a share of the shorter side, a colour and an opacity, and the text is drawn into the pixels when you download.

Questions

How large should the watermark be?
Four per cent of the shorter side is small enough to stay out of the way but large enough to read on a phone. Raise it toward ten per cent when the picture will be shown at a large size.
Why is there a dark outline?
White text disappears on a bright sky and black text disappears in shadow. A thin dark stroke around the letters keeps them readable on either, and it can be turned off when the background is known.
Can someone remove the watermark?
The text is part of the pixels rather than a separate layer, so removing it means editing the image. A determined person still can, which is why a watermark deters rather than prevents.