How to use
- Drop your file(s) into the box above — or click it to browse.
- Conversion starts immediately; the tabs switch to a different output format. Adjust the quality slider to re-encode instantly.
- Click Download on each finished file — or Download all (.zip) for a batch. Nothing was uploaded at any point.
Why documents get watermarked at all
The common case is sending a copy of an ID card, certificate or contract to a counterparty who only needs to verify it: watermarking "2026-08-16 재직확인용" (or "FOR VERIFICATION ONLY") across the image makes the copy useless for anything else. That habit — recommended by banks and government agencies — only protects you if the watermarking itself doesn't involve uploading the pristine original to a third-party server first. Running the stamp locally closes that loop.
The text is drawn into the pixels — it is not a layer, not metadata, and does not survive as removable data. For photos where you want a subtle brand instead of a protective grid, put a short name and pick JPG at high quality; for evidence-style stamps, longer text tiles denser.
| Property | Behavior |
|---|---|
| Pattern | Diagonal 45° tiles, brick-offset rows, full coverage |
| Contrast | White fill + dark outline — visible on any background |
| Scale | Sized from image diagonal and text length |
| Scripts | Any system font glyph — 한글, kanji, Cyrillic, emoji |
| Output | JPG (with quality slider) or PNG |
When NOT to use this
- You may need the clean image later — the watermark is permanent by design; keep your original.
- Legal certified copies — some agencies require their own stamp format; check first.
- Invisible watermarking — steganographic marks are a different tool; this one is deliberately visible.