Add Signature to Images
Add digital signatures to images. Draw or upload your signature. Perfect for documents, certificates and professional use. High-quality output.
Upload an image to get started
Click anywhere to browse, or paste directly with ⌘V / Ctrl+V
Supports PNG, JPG, WebP, AVIF, GIF, BMP, and ICO files.
Try a sample image
Digital Signature Watermark & Transparent Signature Tool
Apply digital signatures and handwritten author marks onto contracts, photos, and artwork.
How It Works: Step-by-Step Instructions
1. Upload Document or Artwork
Load the file you wish to sign.
2. Draw or Upload Signature
Draw your signature on canvas or upload a scanned transparent signature.
3. Position & Scale
Place the signature precisely where needed and adjust ink color.
4. Download Signed File
Export your securely signed file.
Technical Specifications & Architecture
BitNexa combines HTML5 Canvas, WebAssembly, and modern GPU acceleration to execute professional-grade graphics algorithms directly in the browser sandbox.
Smooth Bézier Vector Inking
Captures touch and mouse strokes using smoothing algorithms for realistic handwriting.
Pro Tips & Best Practices
- ✓Draw signatures using a stylus or touchscreen for the most natural handwritten curve.
Frequently Asked Questions
Common questions about this tool, file formats, and client-side processing.
100% Client-Side Privacy Guarantee
Your files never upload to our servers. All operations execute directly in your web browser.