Ok, I haven't read it, but I will expand on it.
If there is no legal information posted, then it is copyrighted by the owner and you cannot repost. Also, if there is legal information and it forbids it (or doesn't mention) then you also can't repost.
If there is legal information and it says it can be posted anywhere so long as you don't take credit, then go right ahead. Sure you uploaded it, but their name is typically right at the top saying they wrote it.








