Image Watermark

What this tool is used for

• Marking a proof image so it is obviously not the final deliverable.
• Adding a credit line to an image before publishing it.
• Watermarking a screenshot to show it came from a specific environment.
• Marking a draft asset so it cannot be mistaken for approved artwork.
• Adding a discreet attribution to a photograph.

Frequently Asked Questions

Does the image get uploaded?

No. The file is read with the File API, drawn to a `<canvas>` in your browser and re-encoded there — nothing crosses the network, which is the point for a photo you have not published yet.

Does a watermark actually protect an image?

It deters casual reuse and it does not prevent theft. A corner mark can be cropped, and both cloning tools and generative fill remove one convincingly. A mark across the subject survives cropping but damages the image for legitimate viewers too — that is the real trade.

What opacity should I use?

Around 30–50% for a visible-but-unobtrusive mark. Below about 20% it disappears against a busy background; above 70% it competes with the picture. Test on your *lightest* and *darkest* images, since a white mark vanishes on a bright sky.

Is my EXIF data preserved?

No — and that is usually welcome. Re-encoding through canvas drops every metadata block, including the GPS coordinates a phone embeds. Anything you relied on, such as the copyright field or the orientation tag, is gone too, so rotate before you watermark.

Which format should I export?

JPEG for photographs, PNG when the watermark has hard edges or transparency you want to keep. Exporting a photograph as PNG produces a far larger file for no visible gain, since PNG is lossless and photographic noise does not compress.

Where should a watermark sit?

Across content rather than in a corner. A corner mark is removed by a crop that costs the thief nothing, while a diagonal mark over the subject cannot be taken out without visibly damaging the image — which is the entire deterrent.

Does adding a watermark re-encode the photo?

Yes — the image is drawn to a canvas and encoded again, so a JPEG loses a little quality on the way through. Watermark once from the original rather than repeatedly from an already-watermarked copy.

Common errors and gotchas

• Placing the watermark where a crop removes it, which defeats the purpose entirely.
• Making it so faint it is trivially removed, or so heavy the image is unusable.
• Watermarking the only copy, leaving no clean original.
• Assuming a watermark prevents reuse, when it discourages rather than stops it.
• Re-encoding a lossy image to add the mark, which compounds artefacts.