💧 Image Watermark Tool
Add a text watermark to an image — pick the position, size, color and opacity, then download the result. Everything runs locally in your browser.
How the text is sized and placed
The photo is decoded and drawn on a canvas in this page, and the text painted over it - nothing is uploaded. The font size is a share of the image width, not a fixed point size, so the same setting suits a thumbnail and a full-frame export:
font size = round(image width × size% / 100)
padding = round(font size × 0.6)
fill = rgba(your colour, opacity / 100)A 3000×2000 photo at 4% gives 120 px lettering inset 72 px from the edge. Five anchor points are available - the four corners and the centre - drawn once in the browser's default sans-serif.
Getting it right
- Change a control, then press Apply. The sliders and the text box do not repaint on their own; the canvas only redraws when you click the button or load a new file.
- Long text can run off the edge. The line is never wrapped or shrunk to fit, so a long credit at 15% will be clipped at the right - drop the size until it sits inside the frame.
- White at 60% suits most photographs. Below 30% the mark disappears into light backgrounds; above 80% it competes with the picture.
Frequently asked questions
How do I add a copyright notice to a photo?
Type it into the text box - the default is already a copyright line - choose a corner, set the size and opacity, and press Apply. The preview shows exactly what the download will contain.
Why does nothing happen when I drag the opacity slider?
The redraw is tied to the Apply button. Set the text, position, size, opacity and colour first, then click Apply once and both the preview and the download link refresh together.
Can I use my own logo instead of text?
No, this tool paints text only, in the default sans-serif with no font choice. For a logo, add the border or spacing you need elsewhere and composite the two images in an editor that handles layers.