Thumbs Plus seems to contain a full Python installation, with extra TP goodness packaged in; on my Windows 7 system I have C:\Program Files (x86)\ThumbsPlus9\Python, and in that file python.exe and pythonw.exe and the LICENSE.txt, NEWS.txt, and README.txt files that I believe a normal Python install has. Plus the subdirectories with various things in them.
But, when I run (locally, or via PATH) python.exe from there, I get "The program can't start because python27.dll is missing from your computer." And, looking through those directories, there is in fact no python27.dll. (What I tried precisely is, from a Windows command window, "python.exe --version". It clearly found python.exe, but couldn't go much beyond that.)
I do see C:\Program Files (x86)\ThumbsPlus9\Python\libs\python27.lib and also libpython27.a, which suggests that maybe the Python in Thumbs Plus is statically linked rather than built as a DLL, which seems weird off the top of my head but I've never done a Python embedding so I don't know what the issues are. So, in that case, the appearance of having a Python distribution present isn't real, maybe? (And those exe files that look so tempting but can't work under that theory shouldn't be there, then; save space in the installer and on my system, avoid a source of confusion, etc.)
I can of course install another Python installation and do my initial testing on that (I was hoping to use the TP one to avoid having possibly different versions for when I ran something within TP and when I ran standalone). And soon I'll probably (I hope) be tied into TP internals and thus unable to run my scripts anywhere else. This may not make much difference.
But at the moment it looks weird, like an anomaly, and I hate leaving anomalies I don't understand behind me as I dive into things; too often they prove I really don't understand them by biting me in the ass later.
I don't imagine anybody but some of the actual developers can actually *answer* this, and it's probably not important to that many people anyway. But just in case, and to document what I'm doing, I'm posting it.