[1] "I found 4 085 giraffes created by people named Sanne!"
[2] "I found 9 988 giraffes created by people named Ediktonia!"
The actual statistic is that 2% of all Germans who submitted giraffes were named Sanne and 5% were named Ediktonia. It doesn't say they were all the same person.
Sanne has actually only submitted 15 pictures. This is one of them, http://www.onemilliongiraffes.com/?id=54374 There are ~2000 giraffes on one page. Ediktonia has similar images.
Personally, I think these works are kind of taking the piss.