Newfag here, what are the last 3 numbers in filename timestamps for?

the last 3 numbers are milliseconds and 4chan randomly generates them in order to avoid multiple images with the same name being uploaded to the server

>>1552047
>the last 3 numbers are milliseconds
This part is right.
>and 4chan randomly generates them
This part is wrong, they are actual milliseconds. We've seen old code leaks where the number is extracted from the return value of microtime().

>>1552047
ref:
https://desuarchive.org/qa/thread/1436378/#1439008
https://pastebin.com/4JVjS02b

>>1552147
hmm. I thought this was changed because images were being broken in sticky threads. some anons were talking about it in this thread leading up to the 1.5 trillion timestamp http://desuarchive.org/qa/thread/1436378/

i'm interested to know which one is correct now, as there were conflicting opinions in the same thread...