I just noticed that in the MISC TOOLS section, there is an ADS scanner. I thought I'd try it out and see if it found anything on my system, and it did.
It found a bunch of .jpg files and gave results like this:
E:\<directory path>\<image name.jpg> : Q30lsldxJoudresxAaaqpcawXc (10120 bytes)
WTF is this all about?