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ConvertBox

Image Annotator

Annotate images in your browser with arrows, shapes, text, and mosaic redaction. Export as PNG or JPG without uploading files.

✍️

Select an Image

Upload one image to annotate locally in your browser

Max file size: 50MB

or drag and drop · press Enter to browse

How to Use

  1. Upload an image from your device
  2. Choose arrow, rectangle, ellipse, text, or mosaic from the toolbar
  3. Drag on the image to add markup, or click to place text
  4. Adjust color, stroke width, text size, or mosaic size in the properties panel
  5. Export the annotated image as PNG or JPG

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

Frequently Asked Questions

No. Annotation and export run locally in your browser using Canvas.
Yes. Use the mosaic tool and drag over the area you want to pixelate.
Yes. The preview may scale to fit the screen, but export renders at the original image dimensions.
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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