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OS Authority

Add a watermark to your photos

Put your name, shop or logo on photos before you post or send them, in one go for a whole batch. Your photos never leave your device.

Your photos are processed on this device and never uploaded. We don't see, store or log your files.

How it works

  1. Tap Choose files and pick the photos.
  2. Choose Text and type it, or choose Logo and pick your logo image.
  3. Set the position, size and opacity.
  4. Tap Add watermark, then download the photos, all of them as a ZIP, or share them.

Why watermark here

Unpublished product photos and client work stay on your device: your own browser adds the watermark. There is no account and no watermark of ours on your photos.

Text or logo

Text can be in any language, including Arabic and Urdu, and gets a thin outline so it stays readable on light and dark photos. A logo works best as a PNG with a transparent background; JPG logos keep their background box.

Size, position and opacity

Size sets the watermark's width: small is 15% of the photo's width, medium 25% and large 40%, so it looks the same on every photo in a batch whatever its resolution. Corners keep the subject clear; Tiled repeats the mark across the whole photo, which is harder to crop or edit out. 30% opacity is subtle, 50% is the usual choice and 80% is bold.

What happens to the photos

Photos keep their full size and are saved as JPG at quality 90; PNG images stay PNG, with transparency. Rotation from the camera is applied. Details such as the date and location aren't copied into the new files. You can mark up to 20 photos at a time on a phone, 50 on a tablet and 100 on a computer.

Frequently asked questions

Can I use my logo?

Yes. Choose Logo and pick a PNG, JPG or WebP image; a PNG with a transparent background looks best.

Will the watermark look the same on every photo?

Yes. Its size is set as a share of each photo's width, so portrait, landscape and small photos all get the same look.

Can a watermark be removed?

Any visible mark can be cropped or edited out with effort. Tiled watermarks over the whole photo are the hardest to remove.

Are my photos uploaded?

No. Everything happens in your browser on your own device.

Last reviewed: October 3, 2026

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