Zellio.io

Watermark Adder

Overlay custom text or a logo onto any image, then download it.

Runs locallyWorks offlineShare link carries settings, never your data
Send output toMeme GeneratorImage CompressorEXIF Viewer & RemoverBuild a workflow from thisOutput stays on this page until you send it.

Frequently asked questions

Are my images uploaded to add a watermark?

No. Everything runs locally in your browser using standard web APIs — your text, files and inputs are never uploaded to a server, so the tool works even offline once the page has loaded.

Can I use my own logo as the watermark?

Yes. Add a text watermark or upload a logo image, then control its placement and opacity before exporting. You can use a PNG or SVG logo, adjust its size to match your image dimensions, and position it anywhere on the canvas — corner, center, or tiled across the entire image for maximum coverage. The opacity slider lets you make the logo subtle for branding or dark enough to deter theft, and you can preview the result before downloading. This is ideal for photographers protecting proofs and creative professionals protecting unpublished work.

Will the watermark reduce image quality?

No — the original image is preserved and the watermark is composited on top. You download a clean copy with your overlay applied, with no loss to the underlying image data or resolution. The watermark is added as a new layer on top of your original image, so the image quality remains unchanged — you can always re-download a clean, unwatermarked copy if needed. This non-destructive approach means you can experiment with different watermark placements and opacities without degrading your original asset.

Pro tips

  • Place the mark over the subject, not the background. A corner watermark on a flat sky is a thirty-second edit to remove.
  • Tile a repeated mark across proofs you are sending to a client, where deterrence matters more than the image looking pristine.
  • Watermark last in your pipeline, after cropping and resizing, so the mark ends up the size you intended.
  • Include something identifying rather than decorative — a name or domain does more for you than an abstract logo if the image travels.
  • Keep opacity high enough to survive a screenshot and a re-compression; a very faint mark disappears into JPEG artefacts.

About Watermark Adder

A visible mark is a deterrent rather than a lock — it discourages casual reuse without preventing a determined crop. Placing it across the subject instead of in a corner is what makes it awkward to remove.

Protect your photos and graphics by overlaying custom text or a logo, then adjust the position, size and opacity until it looks right and download the result. A subtle watermark deters unauthorised reuse of product shots, proofs, screenshots and creative work.

Add a semi-transparent copyright line, or tile a logo across the whole canvas so a crop cannot simply remove it. Position, size and opacity are all adjustable until the mark sits where it does not fight the subject.

Placement is a straight trade between how easily the mark is removed and how much it spoils the image. A small corner mark is unobtrusive and a crop away from gone. A large low-opacity mark across the middle is much harder to remove and much more visible to the people you actually want looking at the picture. Most useful settings sit between: text large enough to read at thumbnail size, around 30 to 50 percent opacity, positioned over detail rather than flat background where it would be simple to paint out.

Two practical details decide whether a watermark survives contact with the real world. Apply it after resizing, or the mark scales with the image and can end up illegible at the size actually published. And keep an unmarked master — you will eventually need a clean version for a licensed use, and re-creating one from a watermarked export is not possible.

Common use cases

  • Photographers sending proofs to clients before payment, where the shots need to be judged but not used.
  • Sellers marking product photography that is routinely scraped and reposted by other listings.
  • Designers circulating draft artwork that should not be mistaken for final approved assets.
  • Anyone sharing a document scan or screenshot who wants a visible record of where it came from.
  • Teams marking internal images as confidential or draft before they are circulated more widely.
How it comparesDesktop editors offer blend modes and batch actions a single-purpose tool does not, and Photoshop is a heavy way to add one line of text. The meaningful difference from upload-based watermarkers is that a proof you have not been paid for is never handed to a third party in order to mark it.