How to watermark images fast (without uploads)

This guide shows how to watermark images entirely in your browser so files never leave your device, while keeping your site fast by exporting modern formats.

1) Use in‑browser processing

• Drag & drop your images into The Watermarker. Everything runs locally via Canvas/WebAssembly.
• Adjust text/logo, opacity, diagonal/tiled placement. Preview instantly before export.

2) Export WebP/AVIF for speed

• WebP/AVIF deliver much smaller files at similar quality than PNG/JPEG, improving Core Web Vitals.
• Start with WebP quality 75–85%; for AVIF, 45–65% often works well. Compare visually.

3) Pick the right placement

• Diagonal or tiled provides stronger protection. Corner/center is easier to read.
• Use 20–35% opacity for a balance of protection and aesthetics.

4) Batch workflow tips

• Reuse consistent text/logo, color and opacity across your library.
• Keep a preset of your preferred settings and apply them in one go.

5) Invisible watermark (optional)

For attribution, add an invisible watermark (DCT/QIM). It survives light compression and resizing; verify on the “Verify” page by decoding with the same seed/length.

Checklist

• Visible: diagonal or tiled, 20–35% opacity
• Export: WebP/AVIF, quality tuned by eye
• Invisible: short ID payload for attribution (optional)