Screen Shot manager read order

That I know, which due to computer number reading order means that a shot taken in September last year shows up after one taken in January of this one.  I'm wondering about the in-game screen shot manager, which seems to have its own, and different way of showing photos that differs from the folder.  It starts off with earliest first, in order, then after about a dozen or so starts scrambling them up regardless of how the shots in the folder are numbered.

Per your suggestion of a few months ago, each household now has its own screenshots folder, all but one of which are in original date order.  I decide in advance which family I will play and designate their folder as 'screenshots' before launching game.  The others are 'screenshots [household flag]'.  I can compare how the manager displays the 2 types of photo numbering, and both get scrambled from the as taken order.