If you've searched for this before or being otherwise snooping through the shell's exported functions, you may have seen something called SHGetUserPicturePath or its ex version SHGetUserPicturePathEx. Just the sound of their names elicit sounds of joy, a joy that the long search is over. And it should be, except that it isn't. For one thing, up until a few weeks ago there was no public record of how to use them or what they do, at least not one picked up by Google. Now that's been rectified (with the docs above) and given the MSDN page, 2+2 would suggest these are the functions called upon opening the control panel.
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