Add Watermark to Images - Text, Logo, Batch

What does this watermark tool do?

This tool stamps a text or logo watermark onto your images entirely inside the browser. Drop up to 100 images, set the watermark once, and every image in the batch gets the same treatment. You control opacity, rotation, size, and position, and you can switch from a single corner mark to a fully tiled pattern. Individual images can break away from the shared setup when one photo needs something different.

Key features

• Text watermark with multi-line support, font choice, color, and bold.
• Image or logo watermark from any PNG, JPEG, or WebP file, aspect ratio preserved.
• Single placement on a 3×3 anchor grid: the four corners, the four edges, or dead center.
• Tiled watermark that repeats across the whole image with adjustable horizontal and vertical spacing.
• Diagonal traceability watermark: dense, faint, tilted tiling that survives cropping and re-sharing.
• Opacity from 1% to 100%, free rotation from -180° to 180°.
• Size in percent of the image's shorter edge, or in absolute pixels, switchable at any time.
• Shared settings for the whole batch, with per-image overrides when you need them.
• Output to JPEG, PNG, or WebP, or keep the original format.
• Fully local: nothing is uploaded, files stay in your browser.

How to use it

1. Drop images onto the upload area or click to browse.
2. Pick a preset to start from, or choose text or logo as the watermark type.
3. Adjust size, opacity, rotation, and position. The preview updates as you go.
4. Switch to tiled placement if you want the watermark repeated across the image.
5. To treat one image differently, select it and click "Adjust this image only".
6. Press "Add watermark to all", then download files one by one or as a ZIP.

Percent or pixels?

Percentages are measured against the shorter edge of each image. A 6% watermark is 180px tall on a 4000×3000 photo and 36px on an 800×600 thumbnail, so a mixed batch stays visually consistent. Absolute pixels are the right choice when every image is the same size and you need an exact match. Switching units converts the current values using the selected image, so the watermark keeps its appearance.

About diagonal traceability watermarks

A tilted, low-opacity, tiled watermark is often called an anti-screenshot watermark. It does not prevent anyone from taking a screenshot. What it does is make a leaked screenshot attributable: when each recipient gets a copy stamped with their own name, ID, or timestamp, a leaked image points back to a single source. That deterrent is the actual value, and it works even when the leaked copy is cropped, because the pattern repeats across the entire image.

For the same reason, a visible watermark is not copy protection. Anyone determined enough can retouch it out. Use it to discourage casual reuse and to establish provenance, not as a security control.

Privacy and security

Every image is decoded, composited, and re-encoded locally inside your browser tab using the Canvas API. No image and no watermark text is ever uploaded to a server, and nothing is stored after you close the page. Object URLs are revoked when you remove files or leave the page. This matters more than usual here, because watermark text often contains a real name, an employee ID, or a contract number.

FAQ

Can I watermark many images at once?

Yes. Add up to 100 images, configure the watermark once, and press "Add watermark to all". Images are processed a few at a time and can be downloaded individually or as a single ZIP.

Can different images use different watermarks?

Yes. By default every image follows the shared settings. Select an image and click "Adjust this image only" to give it its own watermark; the queue marks it as custom. You can send it back to the shared settings, or promote its settings to become the shared ones.

Which fonts are available?

Sans-serif, serif, and monospace. The tool deliberately uses your system's generic font families instead of downloading a webfont, which keeps the page small and works offline. Chinese, Japanese, and Korean text renders with your system's font for that script.

Does the watermark reduce image quality?

The pixels under the watermark are replaced, and re-encoding to JPEG or WebP applies lossy compression at the quality you choose. Export as PNG, or keep the original format when the source is a PNG, to avoid any additional loss.

Is there a file size limit?

Processing happens on your device, so the practical limit is your available memory. Ordinary phone and camera photos are fine. A tiled watermark on a very large image draws many copies, so the tool caps the tile count to keep the page responsive.