The problem is that both versions of OpenCV have memory leaks in very basic functions such as cvtColor(). Running of such a program results in many page faults and memory consumption is increasing. StevenM do you have the same experience?
No, I haven't had this issue with Python, but memory management is a lot more complicated in c++. I've seen this issue pop up for a lot of c++ users, and some furious about it - but it does look like these problems have solutions. OpenCV is used in a lot of serious applications and is updated quite a bit. A memory leak like that should certainly not exist.