What is an image watermark?
A watermark is a visible mark placed on an image to show who made or owns it, usually a name, website address or copyright line. This tool writes one line of your text in the bottom-right corner of a picture, in semi-transparent white with a thin dark outline, and lets you download the result as a PNG.
A watermark doesn't stop someone copying an image, and a small corner mark can be cropped out. What it does is keep your name attached to the picture when it's shared without credit, which is why photographers, artists and shops use them on preview images.
How to watermark an image
- Click Choose File and pick an image.
- Type your text in Watermark Text, for example
© 2026 Jane Smithorjanesmith.photo. - Click Convert and check the preview.
- Click Download to save
watermarked.png.
If the text box is empty, you'll see "Enter watermark text." Leading and trailing spaces are trimmed.
What the watermark looks like
The style is fixed and designed to stay readable on both light and dark photos:
| Property | Value |
|---|---|
| Position | Bottom-right corner, right-aligned |
| Font | Bold, the browser's default sans-serif |
| Size | Image width ÷ 20, minimum 14 px |
| Fill | White at 60% opacity |
| Outline | Black at 40% opacity, about 1/20 of the font size thick |
| Margin | Half the font size from the right and bottom edges |
Because the size scales with width, the watermark looks about the same on a small preview and a full-resolution file.
Worked example
Take a 1200 × 800 product photo and the text shop.example.com.
- The font size is 1200 ÷ 20 = 60 px, bold.
- The outline is 60 ÷ 20 = 3 px wide.
- The text's bottom-right corner sits 30 px in from the right edge and 30 px up from the bottom.
- You download a 1200 × 800 PNG with the address in the corner.
On a 200-pixel-wide thumbnail, 200 ÷ 20 would be 10 px, so the 14-pixel minimum applies instead.
Tips for an effective watermark
- Keep it short. The text is drawn on one line with no wrapping or automatic shrinking, so long text on a narrow image runs off the left edge. A domain name or
© Namefits comfortably. - Watermark a copy, not the original. Keep your unmarked master file and share the watermarked version.
- Resize before you watermark. If you're posting a smaller version online, resize it first with the image resizer, so the text is scaled for the size people will actually see.
- Use the © symbol properly. The usual form is © followed by the year of first publication and the owner's name. Under the Berne Convention, which most countries have joined, copyright protection doesn't depend on any formality such as a notice, so the mark is a reminder rather than a requirement.
What happens to the file
The image is drawn onto an HTML canvas at its full size, the text is painted on top with the canvas text drawing API, and the canvas is exported as PNG with toDataURL('image/png'). That has a few consequences:
- The output is PNG, even for a JPG input. Transparency in a PNG or WebP source is kept. File size for photos goes up; the image compressor converts the result back to a JPEG at the quality you choose.
- Metadata is removed. EXIF data, including any GPS location, isn't copied into the watermarked file. If you want that without a watermark, the EXIF remover does only that step.
- Animated images become stills. Only one frame of a GIF or WebP animation is kept.
- The text is part of the pixels. Once saved, it can't be edited or removed as a separate layer, which is the point of a watermark, but it also means you need the original to change the wording.
If you'd rather share the image as a WebP for a smaller web-friendly file, run the watermarked PNG through the WebP converter.
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