Bulk Watermark Images
Stamp a text or logo watermark across a whole batch of images and download them as a ZIP. Position, opacity, size, rotation, and a tiled repeat — all rendered in your browser, nothing uploaded.
Drop images here or click to browse
Add as many as you like — processed locally
What a watermark does, and the one thing it cannot do
A watermark is a visible ownership mark laid over an image — your name, a copyright line, or a logo — sitting on top of the picture so it travels with every copy. It does two useful jobs: it credits you wherever the file ends up, on a repost, a scraped listing, or a screenshot, and it signals that a clean, higher-resolution version exists behind a licence or a paywall.
What it does not do is make the image theft-proof, and any tool that promises that is overselling. A watermark is a deterrent, not a lock. A determined person can crop a corner mark off, clone it out, or run a modern inpainting model that reconstructs the pixels underneath. This tool is built to raise the effort and the ugliness of doing that — not to pretend it is impossible — and the settings below are the levers that decide how much effort it takes.
Text or logo, and when each wins
There are two watermark types. A text mark is the fastest: type a line such as a copyright symbol and your name, pick a colour and a size on the 10–120 slider, and you are done, with nothing to prepare in advance. A logo mark uploads an image instead, and a transparent PNG is the right file for it — a logo saved as a JPG carries an opaque white box that will sit as a hard rectangle on top of your photo.
The logo is scaled to a share of the image width, from 5 to 60 percent, and its height follows automatically so the aspect ratio is never distorted. We confirmed this: a 200×50 logo set to 20 percent of an 800px-wide image renders at exactly 160×40 — the original 4:1 shape preserved to the pixel. Text suits attribution and quick proofs; a logo suits brand consistency across a catalogue.
The six positions, and why tiling is the strongest
You get six placements: the four corners, dead centre, and a tiled repeat. A single corner mark is clean and unobtrusive, which is what you want when the goal is a credit line rather than a barricade — but it is also the easiest to remove, because cropping off one corner or painting over one small patch takes seconds. Centre is more intrusive and harder to ignore.
Tiling is the strongest of the six, and it is worth understanding why in concrete terms: instead of one mark the tool stamps a full grid across the frame. On an 800×600 image with the default text, that is 15 separate copies — five columns by three rows — on a 441×136 pixel step, covering the picture from roughly 106 pixels down to 563. To defeat that, an attacker has to reconstruct all 15 covered patches across the whole image rather than trim one edge — far more work, and far more likely to leave visible damage. It is the right choice for high-value previews; a corner mark is fine for everything else.
Opacity, size, and rotation, in numbers
Three sliders control how the mark looks. Opacity runs from 5 to 100 percent and is applied as the canvas global alpha before the mark is drawn, so at the default 60 percent a white mark blends to a soft grey near 153, 153, 153 that stays legible without burying the photo underneath.
Size for text runs from 10 to 120, but the number you pick is not a raw pixel height — it is tuned against a 400px reference and then scaled to the actual image, using scaled font = size ÷ 400 × image width, with an 8px floor so it never vanishes on a small image. That is deliberate: a setting of 32 produces a proportional mark whether the photo is 400px wide or 4000, so a batch of mixed-resolution images comes out consistent instead of the mark appearing tiny on the large files and huge on the small ones. On an 800px-wide image, 32 becomes a 64px font; on a 4000px-wide one it becomes 320px. Rotation runs from −90 through 0 to +90 degrees, and a diagonal mark is both harder to crop around and harder to clone out than a flat horizontal one.
Batch processing and the ZIP, without an upload
The point of this tool is volume. Marking one image in a desktop editor is trivial; marking 200 catalogue photos by hand is not, and that is the job it is built for. It applies the exact same settings across every image you load, previews them live on the first one so you can tune before committing, and then writes the results.
A single image downloads on its own; two or more are bundled into one ZIP file, built in the browser with JSZip, named so each output keeps its original filename with a watermarked suffix. Every image is exported as a PNG, which is lossless and keeps the mark and any logo transparency crisp rather than softening edges the way repeated JPG compression, with its 8×8 pixel blocks, would. If you need to shrink the results afterward, the image compressor gives you a quality slider with a live size readout.
Why local processing matters here in particular
Most watermarking is a paradox online: the service asks you to upload the original, unmarked, full-resolution file — exactly the asset you are trying to protect — to a server you do not control. If that service logs uploads or is breached, the clean version you wanted to keep private is the one that leaks.
This tool renders every image on the browser canvas, so the originals never leave your device, not on the way in and not on the way out. For unreleased product photography, a client gallery under embargo, or confidential design comps, that is the difference between a private workflow and handing your unmarked files to a third party. The watermark protects the copies you share; keeping the process local protects the original you do not.
Every setting and fact, by the numbers
There are two watermark types — text and logo — and six positions: four corners, centre, and tile. Opacity spans 5 to 100 percent, applied as global alpha. Text size runs 10 to 120 against a 400px reference, so a value of 32 renders as a 64px font on an 800px-wide image via size ÷ 400 × width, with an 8px floor. Logo scale runs 5 to 60 percent of image width with height locked to the original ratio; a 200×50 logo at 20 percent verified as exactly 160×40.
Rotation spans −90 to +90 degrees. The margin is 3 percent of the shorter side — 18px on an 800×600 image. Default text tiling on that size lays down 15 copies (five by three) on a 441×136 pixel step, spanning 457 of the 600 vertical pixels. Output is always a lossless PNG; one image downloads directly and two or more arrive as a JSZip ZIP. Nothing is uploaded. And the one fact worth repeating: a watermark deters copying, it does not prevent it — so tile the high-value work and keep your originals local.
How to Use
Upload one or more images (JPG, PNG, WebP).
Choose a text watermark, or upload a logo — a transparent PNG works best.
Set position, opacity, size, and rotation while watching the live preview on the first image.
Pick a corner for a light credit line, or Tiled for a repeat that is harder to crop out.
Download a single image, or all of them together as a ZIP.
Features
Common Questions
About Bulk Watermark
Add a text or logo watermark across many images at once. Control position, opacity, size, rotation, and tiling, preview changes live on the first image, then download a single watermarked image or the whole batch as a ZIP. Everything is rendered on the browser canvas, so your originals never leave your device.
Also known as: add watermark, bulk watermark, watermark photos, batch watermark, protect images watermark, logo watermark, tiled watermark, watermark multiple images, copyright photos, stamp images.
Processing Note
Bulk Watermark runs in your browser, so the input you enter is processed locally on this page and is not uploaded to a ToolMintX account.
Tool Limits
Image tools can optimize and transform files, but source quality still matters. Blurry, over-compressed, or badly lit images may need a better original before editing.
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