Image Watermarker
Stamp text or an overlay image onto any photo — 9-position grid, opacity, padding.
Overview
The Image Watermarker stamps either a text caption or an overlay image (such as a logo) onto a base photograph, with controls for one of nine anchor positions, padding, opacity and scale. Upload your base, supply text or upload an overlay, configure placement, and the tool returns a watermarked image ready for download.
It is the right tool when branding a portfolio export with a logo, attributing photography across a recipe blog, applying a "SAMPLE" stamp over preview shots, or generating consistent watermarks on a folder of mixed-size images. The nine-position anchor grid keeps the mark in the same relative place regardless of the source dimensions.
How it works
The base image is decoded into a pixel buffer and the overlay is composited on top using the source-over Porter-Duff blending equation, scaled by the opacity slider. For text watermarks the renderer draws glyphs at the chosen font size using sub-pixel anti-aliasing so the strokes remain smooth at any zoom. For image overlays the logo is first resampled to the requested scale percentage using a Lanczos filter.
Anchor positions follow a 3x3 grid (top-left, top-centre, top-right, centre-left, ..., bottom-right). The padding value insets the watermark from whichever edges the anchor touches — a bottom-right anchor with 32 px padding sits 32 px in from both the right and bottom edges. The output is re-encoded in the source format at near-original quality.
Examples
Before: 4000x3000 photo
Overlay: 512x512 logo, opacity 70%, scale 50%, bottom-right, padding 40
After: 4000x3000 photo with the logo at 256 px square,
40 px from the right and bottom edges.
Before: 1080x1080 social square
Overlay: text "@studio_name", top-right anchor, padding 24, opacity 80%
After: Branded social tile ready for a feed.
Before: 1920x1080 hero shot
Overlay: text "SAMPLE", centre anchor, opacity 40%, large font
After: Preview shot with a translucent "SAMPLE" diagonal banner.
FAQ
Text or image — which should I pick?
Text is best for simple attribution lines. Image overlays make sense when your watermark is a real brand logo with custom typography that wouldn't render correctly from a font dropdown.
Will the watermark survive screenshot tools?
It is rasterised into the pixels, so anyone re-saving the image keeps the watermark. Removing it requires inpainting — easy for a small corner mark, hard for a centred translucent banner.
Can I tile the watermark across the whole image?
The bundled implementation places one watermark at the chosen anchor. For tiled patterns, layer two passes (each with a different anchor) or render the watermark into a transparent overlay first and stamp that.
Does opacity affect text differently from images?
No — both use the same source-over equation. Opacity 70% means 70% of the watermark colour and 30% of the underlying pixel show through.
What formats can I upload?
The base supports JPEG, PNG, WebP and similar. The overlay must be a format with alpha (PNG or WebP) if you want transparent backgrounds.