Watermark a whole folder of photos

How Batch Image Watermark works

The image is decoded into a canvas element, redrawn, and handed back as a new file. A canvas lives in the tab; closing it discards the pixels, which is why nothing needs deleting afterwards. Nothing is re-encoded on a server, so no copy of the original survives anywhere you cannot see.

That is the whole architecture: static files, one script, no upload endpoint to leak or log. Close the tab and the work is gone.

Why a tiled mark beats a corner

A single corner watermark is a cropping instruction: anyone who wants the image without it removes twenty pixels from one edge. A tiled pattern at low opacity is spread across the whole frame, so removing it means either cropping into the subject or retouching every repetition. That is the difference between a deterrent and decoration.

The trade is cleanliness. A tile is visible on the picture, so use it on proofs and previews rather than on the file you are selling — and keep the opacity low enough that the subject still reads.

What a watermark can and cannot do

It discourages casual reuse and makes provenance obvious when an image is reposted without credit. It does not prevent reuse: any mark laid over pixels can be removed with enough patience, and no browser tool changes that.

What it does do cheaply is establish a claim. A visible name and a date on a preview is evidence of who published first, which is the part that matters in a takedown request or a dispute.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions