For a while I sold prints and merchandise based on my own illustrations. One image was listed in my shop when I spotted it as the main image of someone else's store on another platform. Only the small credit in the bottom-right corner had been cropped out. Worse, they had taken the compressed copy I posted on social media, so the detail was incomplete, and it took me two weeks just to gather evidence. Since then I have rearranged the whole routine of what to do before posting an image. A watermark is only one step, and its role needs to be clear from the start: it will not stop someone who is determined, but it makes the job more work.
1. Separate two goals: credit the source, or raise the cost of copying
These two goals often get lumped together as adding a watermark, but the methods pull in opposite directions.
- Credit the source: make it obvious at a glance whose image it is. Put a low-opacity credit in a corner or along the bottom edge, with appearance first.
- Raise the cost of copying: make it impossible to grab and reuse as-is. Put the watermark over the subject or tile it across the whole image, letting protection win over appearance.
One more point matters far more than the watermark: proof of ownership does not come from the watermark. What proves an image is yours is the layered source file (PSD, AI), the RAW or original file with capture metadata, and the time and platform of first publication. Cropping out a watermark does not invalidate that evidence. Conversely, a watermark without a source file is not a strong position. So my first recommendation is to keep the source files and publication records before talking about anti-theft measures.
2. Choosing position, density and opacity
| Approach | Best for | Work needed to remove it | Settings I usually use |
|---|---|---|---|
| Single corner credit | Showcase images, portfolios | Crop about 8% off the edge and it is gone, in seconds | Opacity 30%-40%, type size about 1/25 of image width |
| Semi-transparent centre mark | Medium-risk previews | Cover or retouch, ten minutes or so | Opacity 20%-35%, over the subject rather than empty space |
| Full tiling | Stock assets, unpaid custom work | Retouch tile by tile, tens of minutes to hours | Repeat the mark 6-10 times, opacity 35%-55% |
| Over key texture | Product detail, patterns | AI retouching tends to distort edges | Rotate 30°-45°, crossing the outline |
The most valuable phrase in that table is where to put it. A watermark in a flat empty area might as well not be there: flat colour is the easiest thing to fill in one pass, leaving almost no trace. Put it over texture, a gradient or the subject outline, where any edit damages the image itself.
3. My current export workflow
- Leave the source file alone and save a separate public version. Do all processing on that copy.
- Resize the public version to about 1600 px on the long edge. That is enough for social media and product pages, but anyone trying to reprint from it will get a blurry result. This is the cheapest layer of protection, more practical than any watermark.
- Add a text watermark containing something that leads back to the source, such as account name plus platform. An all-rights-reserved line is useless; anyone can type those words.
- For a logo, upload a transparent PNG. A pale logo on a dark background will smear, so raise opacity or size if needed.
- Tile every unpaid custom piece and stock preview. Set the row and column spacing yourself, dense enough to protect the main structure. These images are not meant to be admired.
- After export, inspect at 100%. When JPEG compression is aggressive, noise appears around the strokes of semi-transparent text. Rather than accept that, give back one quality step.
I do steps 3 to 5 in the browser: Image Watermark handles both text and image watermarks. Drag the position directly on the preview and adjust angle, size and opacity; in tiling mode you set the row and column spacing, and changes appear immediately. Processing happens locally, so the image never goes to someone else's server, which is the main reason I use it for ID documents. If the export is too large, run it through Image Compressor, which lets you set quality from 10% to 100% and shows the before-and-after size.
4. ID documents and contracts are different
For ID cards, contracts, quotations and bank statements, the point of a watermark is not to claim copyright but to limit use. Write something like "For identity verification on this platform only; invalid elsewhere" and place it diagonally at 30° across the signature or a key field. That works far better than a neat mark in the corner.
But there is a limit: a semi-transparent watermark does not hide the text underneath. Information that truly should not be seen, such as the middle of an ID number, a card number, an address or an amount, needs redaction, not pale text on top. Image Mosaic lets you select an area and pixelate it, with block sizes from 4px to 80px; for sensitive fields, go coarse enough that the value cannot be read even when enlarged. Two more details: if a phone photo is acceptable, do not send a high-resolution scan, which is sharp and editable; and remove real names from filenames before sending.
5. Common questions
Q: Does a watermark make an image theft-proof?
No. It changes cost and probability, not the outcome. Tiling over texture may make a casual copier pick another image, but it will not stop someone who edits images for a living. Use watermarks together with limited export size, retained source files and publication records.
Q: What opacity should a watermark use?
For showcase images, 25%-40%: nearly invisible at a glance, but legible enough to identify the source when enlarged. For anti-theft previews, start at 50%, or 35%-55% when tiling. The test is not whether it looks comfortable but whether it can be removed with a single fill in an image editor.
Q: Does dense tiling hurt buyers viewing the image and reduce sales?
Yes. My rule: for a product that is priced and ready to sell, use only a corner credit and keep the centre clear. Tile only when the image must be seen before payment, then deliver a clean original after payment. Both sides avoid a loss that way.
Q: What if someone crops out part of a watermarked image?
That is why a corner credit alone is useless. To resist cropping, let the mark cross the middle of the image or sit on the subject outline, or tile it. A crop can remove corners, but not something that runs through the frame; the trade-off is that the image is essentially ruined.
Q: Are ID images uploaded when processed online?
Tools in this category process images in the browser, so the file is not uploaded to a server. Still, build the habit: delete temporary copies afterwards and do not handle sensitive material on a public computer.
I never recovered the sale from that image with the cropped credit, and the platform appeal moved slowly. But the episode changed three things in my workflow: limit the long edge of every public version, tile unpaid work outright, and keep the source file and first-publication record separately. Deciding whether to add a watermark, and how dense to make it, comes down to one question: is this image harder to steal than it is valuable in my hands? A faint credit is enough for showcase work; custom pieces and stock previews deserve full tiling; for ID documents, the priority is redaction, not watermarking.