Zellio.io

Watermark Adder

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

Processed locally — nothing is uploaded

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.

Learn how this works

How to Edit Images in the Browser Without Uploading ThemCompress, watermark and strip metadata from photos entirely on your device — why client-side image editing is faster and more private.8 min readPNG, JPEG, WebP or SVG: How to Choose an Image FormatA practical guide to picking the right image format — what each one is good at, where each falls down, and how to decide quickly.6 min read

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 This is ideal for photographers protecting proofs and creative professionals protecting unpublished work.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.

More Watermark Adder tools

Add a Watermark for Free

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