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ConvertBox

Add Watermark

Add text or image watermarks with custom opacity, position and rotation. Batch up to 50MB per file, output as JPG/PNG/WebP — no upload required.

©️

Select Image Files

Add watermark to multiple files at once

Max file size: 50MB • Multiple files allowed

or drag and drop · press Enter to browse

How to Use

  1. Select image files
  2. Enter watermark text and choose position
  3. Adjust opacity as needed
  4. Download watermarked images
  5. Verify the output file in your device's download folder.
  6. You can adjust settings and process new files immediately without any restrictions.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

Yes, you can set the opacity from 0% (invisible) to 100% (fully opaque) using the slider.
Currently, text watermarks are supported. You can position them in 5 different locations.
Yes, select multiple images to apply the same watermark to all of them.
No. All operations are processed entirely inside your browser's local sandbox using client-side APIs (like WebAssembly, pdf-lib, or HTML5 Canvas). Your files and data never leave your device.
The tool is completely free with no usage limits. However, since processing occurs in your browser's memory, we recommend keeping file sizes under 50MB (especially for heavy files like PDFs or videos) to ensure stability.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

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