My rankings are completely messed up as well. I have 18K photos which should put me in around the top 50, but my period rank is 100 and my overall is 289. When I check my rank in the list it says that I have around 8k photos. I think it's a problem with their updating rank function.
Same for me, i am in overall ranking always at around rank 850-900 even if i went to sleep and got 0 additional photos. When i check my rank up its correct, while my period ranking is 1450ish and when i look that one up its wrong and i find myself among the 850s
Now i have no clue if i am within the top 1000 or not.
period 1853, event 1375. Havn't had time to aim for the top 1000 this one :P seems like the lower your rank, the bigger the gap between the 2
Nutaku has changed something in PeroPero Shop, maybe it reset ranking.
The problem with the rankings appears to be fixed now.