Image Watermarker — Add a Text Watermark in Your Browser

The Image Watermarker draws a line of text over your photo and hands back the combined image as a PNG. You control the text, colour, opacity, font size, bold, italic, drop shadow, and which of six positions it lands in — four corners, dead centre, or tiled diagonally across the whole frame.

Everything is drawn with the HTML5 Canvas API in your browser. The photo is never uploaded. That matters more here than on most tools: watermarking is usually something you do to work that is not published yet — client proofs, unreleased shoots, draft artwork — and those are exactly the files you should not be handing to a stranger's server to process.

The watermark is composited at your image's full resolution, not the preview's. What you download is your original pixels with text burned into them, at the size the camera or export produced. The preview is scaled to fit the panel; the output is not.

This is the one setting people get wrong, and it is worth understanding before you download anything. The font size slider is in pixels of the original image, not pixels of the preview panel or of your screen.

So the default of 28px looks correct in a preview scaled down to about 500px wide — and then produces a watermark roughly 1.4% of the width on a 4000px photo out of a modern camera. On the downloaded file it is a barely legible speck in the corner. Conversely, 28px on a 600px web thumbnail is a heavy band across the frame.

A usable rule: aim for the text to occupy 2–5% of the image's long edge. On a 4000px photo that is a font size somewhere around 80–200; the slider tops out at 80, so on very large originals you will want to resize the photo down to its final delivery size before watermarking rather than after. That is the right order anyway — resize, watermark, compress — because a watermark applied before a downscale gets softened by the resampling.

The preview is honest about proportions even though it is scaled: if the watermark looks small in the preview, it will be small in the file. Trust the preview's relative size, not its absolute one.

Where you place a watermark significantly affects both its effectiveness and the visual quality of the image. Different positions serve different goals:

Bottom-right (default): The most common watermark position by convention. It sits below and outside the main focal area of most photographs without obstructing the subject, is difficult to crop out cleanly without removing part of the image composition, and is where most viewers expect to look for attribution.

Bottom-left: An alternative to bottom-right that works well for images with strong right-side composition elements. Some creators alternate positions across a portfolio to avoid predictable placement.

Centre: The strongest deterrent against removal — covering the primary subject makes the image significantly less useful without the watermark. Used for preview images on stock photography sites and for high-value work being shared before client approval.

Tiled (all over): Repeats the watermark across the entire image at an angle, making selective removal impractical without significant image degradation. Maximum protection for sensitive or high-value work shared in draft or approval contexts.

The most effective deterrent is not necessarily the most visible placement — it is the placement that cannot be removed by simple cropping. Bottom-right corner watermarks are easily cropped out. Tiled or diagonal watermarks covering the central subject are essentially removal-resistant without professional photo editing software.

Watermark opacity is a balance between protection effectiveness and image aesthetic quality. At 100% opacity, the watermark is fully opaque and completely blocks whatever is beneath it. At 10% opacity, it is barely visible and provides little deterrent value. The practical sweet spot depends on the purpose:

Portfolio and social media sharing (30–50%): A subtle watermark that identifies the creator without distracting from the image content. Suitable for final published work where brand association is the primary goal, not theft prevention.

Client review and proofing (60–75%): Clearly visible and readable, making the image unsuitable for use without removal. This is the most common professional use case — clients can evaluate image quality while the creator retains control until payment is received.

Draft and preview sharing (80–100%): Maximum visibility, often combined with tiled positioning. Suitable for sharing preliminary concepts or watermarking stock images sold in preview quality.

Will: overlay up to 60 characters of text on a JPG, PNG, or WebP, in any colour, at 5–100% opacity and 10–80px, with optional bold, italic, and drop shadow; place it in any of four corners, the centre, or tiled diagonally; render it at the image's full original resolution; and do all of it without the file leaving your browser.

Won't add a logo or image watermark. Text only — there is no second file input. See the FAQ below for what to use instead.

Won't preserve your file format, and the output can be much larger than the input. The download is always PNG, because that is what the canvas exports here. PNG is lossless, so a 3 MB JPEG photo can come back as a 10 MB-plus PNG — the pixels are identical but the compression is not. For anything going on the web, run the result through the Image Compressor afterwards and convert it back to JPEG or WebP. For print or archival, keep the PNG.

Won't preserve EXIF, IPTC, or XMP metadata. Drawing to a canvas and exporting produces a fresh file with no metadata at all. Camera settings, capture date, GPS coordinates, and any embedded copyright fields are dropped. That is a privacy win if you were about to post a photo with home GPS coordinates in it, and a real loss if your workflow depends on IPTC credit lines — in which case, watermark first and re-apply metadata with ExifTool, or do both in your editor.

Won't stop a determined thief. A visible watermark is a burned-in pixel overlay, not a technical protection measure and not a copyright registration. Anyone with an editor and patience can remove a corner watermark; content-aware fill removes many of them in seconds. What a watermark actually buys you is attribution when an image travels, friction against casual reuse, and a clear signal that a file was not intended as a free asset. Treat it as deterrence and branding, not security — and never publish the full-resolution unwatermarked file if that matters to you.

Won't handle batches. One image at a time. For a folder of them, use ImageMagick's convert -annotate or your editor's batch processor.