Free · No signup · Private
Watermark Detector
Upload a PNG image to check if it contains a hidden watermark embedded with our tool. Extract and view the secret message instantly.
Drop a PNG image here or click to upload
PNG images only · Must be encoded with our tool
How to Use
1
Upload a PNG image to check
2
Click 'Check for Watermark'
3
If found, the hidden message is displayed
4
Copy the message or try another image
Frequently Asked Questions
How does watermark detection work?
The detector reads the LSB (Least Significant Bit) of each pixel's color channels, looking for a specific magic byte header. If found, it extracts the message length and then the hidden text message.
Can this tool detect any hidden watermark?
No. This tool only detects watermarks created with our Invisible Watermark tool. It looks for a specific encoding format (WMAK header). Watermarks from other tools use different encoding schemes.
Why was no watermark found in my image?
Common reasons: the image was not watermarked with our tool, the image was resized or cropped after watermarking, it was saved as JPEG (which destroys LSB data), or a screenshot was taken instead of saving the original PNG.
Does the image need to be in PNG format?
Yes. Invisible watermarks only survive in lossless PNG format. If the image was converted to JPEG or any other lossy format, the watermark data is destroyed.
Is my image uploaded to a server?
No. Detection happens entirely in your browser. Your image is never uploaded, stored, or transmitted anywhere.
Can I detect watermarks in screenshots?
No. Screenshots re-render the image with different pixel values, destroying any LSB-encoded data. You must use the original watermarked PNG file.
How do I create a watermarked image to test?
Use our Invisible Watermark tool to encode a message into a PNG image. Then download the result and upload it here to verify the message was embedded correctly.
Is this tool free?
Yes, the watermark detector is completely free to use with no limits. No account or signup is required.