问题
I need a program that will embed an invisible mark (not big text info, 256bytes max) in an image. But I could not find a good library (in any language, better if c/c++). I found a lot of literature, but no source code.
I found one resource but that program is writtem for NetPBM format.
The needed method is not LSB, or concating etc.
回答1:
Have a look at steghide, an open-source steganography program that supports JPEG.
回答2:
If you just want to track images with a user id, then you should edit the image EXIF data. There are thousands of libraries out there to do just that. Here is one for C http://libexif.sourceforge.net
来源：https://stackoverflow.com/questions/9113196/digital-watermarking-for-jpeg-png