If they uploaded at the same time, then both are guilty of conspiracy. If they uploaded at different times, then at minimum the second one is guilty.

There might be other factors to take into account that change that result slightly, but it's not really different from a crime that doesn't involve computers.

> If they uploaded at different times, then at minimum the second one is guilty.

You're assuming that you know which one the "second one" is.

The "first" file may have originally been hosted somewhere else or distributed privately. Some hosts don't keep high granularity timestamps or any timestamps at all, or the user may control the timestamp. How do you know who was first?