How to get watermarks from files?

We need to add active and hidden watermarks in my project and verify if they are exist, and these extensions should be supported: pdf;docx;xlsx;pptx;jpg;jpeg;png;webp. How should I verify if the watermarks are exist on these files please? We have found we can use doc.Watermark.Type to judge if we have watermarks on the word document, so do we have any similar functions to judge other extensions? Or do we have any simple ways to judge them please?
Hope for your reply.

Hello, @DeanLX.
We appreciate your interest in Aspose.Imaging.
Firstly, let me notice that Aspose.Imaging can only work with image formats like: jpg,jpeg,png,webp and others, but it can’t load documents like pdf;docx;xlsx;pptx.
Maybe you wished to ask the Aspose.Word team?

Hello, @evgeniy.sidenko
We have found the solutions for word,pdf and excel, but didn’t found solutions for images yet, could you show me the code about how to judge watermarks for images please?

Hi, @DeanLX!
Could you describe what you mean by saying active and hidden watermarks?
Is active watermark a text or image drown over another image?
What is a hidden watermark? Some information is written in the image file but is not visible in the image itself, or something else?

Hi @evgeniy.sidenko
We just add some text watermarks on image which can not be seen by users, we want to know that if we can verify whether watermarks are exist or not by .net code. Do we have any solutions please? And how about the visible watermarks?

Hello, @DeanLX
Talking about visible watermark, you can look at these examples

If you wish to detect that your watermark exists on the image, you can simply get pixels from a region where should be you watermark and then compare these pixels with your signature image.

What about an invisible watermark we can offer using the Xmp Data for storing it, if you have another way to store the invisible watermark, please share it with us for implementation in Aspose.Imaging.