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FAQ | Frequently Asked Questions



Why won't signili let me mark my images?

The following requirements have to be met in the free trial version in order to watermark an image:

The image ...

  • has a maximum filesize of 2,5 MB
  • is at least 300px x 300px in size.
  • has sufficient details (no large monochromatic areas).
  • has a minimum of color variants (or grayscale).
  • isn't a computer generated graphic (vector-based/pixel-based).
  • has been uploaded in JPEG Format (no PNG, SVG, TIFF, GIF, RAW, ...).
  • compression ratio is low enough.


I've uploaded an image and nothing happens. Is this normal?

Depending on the size of the image the upload might take up to 1 minute. The idle time depends on the file size of your image and the speed of your internet connection. If you receive an error message after the lapse of time you should check if your picture meets the requirements for an upload.


Why do I have to enter my email address to mark an image?

We are using your email address to generate your watermark and to later verify that the images is yours.


What do I do with the marked image?

As soon as you marked an image, you should only use this marked version of the image. Only this image contains the watermarking and is capable of comparing suspicious images to your original image.


Do I have to save the detection link?

Yes. Save this email to check suspicious images whether they contain the watermarking. Do not send this email to other people, because they may be able to read your watermarking.


Can I mark a larger amount of images?

signili will soon enroll a "Bulk-Upload" feature. You want to immediately secure a significant amount of images? Then contact us via and we will work out a solution together with you (including our partner, Fraunhofer SIT).



My image contains a watermark but the watermark does not get detected. Why is that?

The image might have been rotated too much, heavily scaled-down or cut. These might be the reasons that cause unreadable watermarking.


How can I test whether my image contains a watermark?

After your image has been marked, you will receive an email from us containing a detection link. This link redirects you to a verifying page, where you can check whether your image includes watermarking. Do not give this email to others, because thus they may be able to read your watermarking.


Can I search the internet for my marked images?

We periodically search the Internet for your watermarked images.

Image Search


What could be the problem, my image hasn't been found yet ?

Image search in the Internet (more specifically the web) usually works with the help of crawlers and a so called searchindex. The crawlers move from website to website, extracting the images on the site, calculating a fingerprint for every image and storing it inside the searchindex. The image thats being searched, also has a fingerprint which is being compared with the searchindex. As a result, our search hasn't produced any results because the searchindex doesn't contain any similar images. Probably, the crawler hasn't yet visited the corresponding website.This might have several reasons:

  • The website hasn't been viewed a lot or has too few backlinks.
  • The website is not publicly accessible to the internet, e.g. because you can only access it with a password
  • Therefore, the missing search results do not imply that its not being used on the web. We periodically search the Internet for your images. Next time, your image could already be among our results.


Why are there no results of similar images displayed ? (for my protection)

If the found image does not contain a watermark, we can not clearly assign it to you and do not show it to you as a find location. This precaution is designed to prevent other users from being able to find out about the locations of your images.


Why did you just find similar images and not my marked image ?

This may have several reasons:

Lightroom Plugin


I've marked my image with the signili Lightroom Plugin. Where is my detection link?

To get an email with your detection link, please mark your image via signili.de . If you need a detection link for individual images, you can send us an email to [email protected] . In this mail, refer to the filename of the selected images.

Background Information


Will the image file get bigger when I mark the image?

Without adding additional data, we use existing image information to embed the watermark. However the file size is slightly changed by the watermarking process.


Will the image quality change due to the watermark?

The image will marginally be changed by the watermarking process. This change can be viewed in the preview window. Using a slider you are able to compare the images.


Why should I trust the watermarking of signili?

The used watermarking algorithm combines nine man years of research and development at Fraunhofer SIT and is practice-approved. With signili it can be used by end-users for the first time.

signili automatically profits from the improvement and further development provided by Fraunhofer SIT.

The watermarking algorithm also identifies images after:

  • size reduction
  • converting to grey scale
  • crops
  • image rotation
  • print/scan
  • photograph


Is signili free?

Yes. You can mark up to 20 images per month via our web application for free, each of them limited to a filesize of 2,5 MB. We search these images on internet for a period of 3 months.

You want to mark more images? You want to mark images of any filesize? Your are using Adobe Lightroom and want to integrate watermarking your images into your current workflow?

Just take a look at our packages!