Can We Use Youtube Screenshots in PDF Reports?

[yourreviewer]

Hello folks,
I am thinking of giving away a free bonus report in pdf which is nothing but a collection of Youtube Videos. Can anyone clarify if it is allowed to capture the screenshots of the video and use it in pdf? Would that be violating the copyrights?

Also I stumbled upon a guide that guides the users to a link which shows how to download youtube videos for free. Now wouldn't that violate the copyrights because technically you shouldn't be downloading youtube videos. And as an author, wouldn't you be held liable for encouraging such an act?

Thanks,
Dan