If you have permission from the owner of the copyright, posting it here is perfectly fine.
Not really...
TPF doesn't enforce all their rules to the same degree.
Verbal permission is not enough according to TPF's rule.
http://www.thephotoforum.com/forum/faq.php
It say's you need permission, that you can
submit to them. (Like in writing so they can have it on file)
The basic idea is, TPF is who would likely be faced with a BS infringement suit and need the permission, not the person that posted the photo.
For many photographers and other creatives, copyright infringement is an everyday issue. Unfortunately, so many people using the Internet think that anything and everything on it is in the public domain, when it's not.
The average person is generally clueless about copyright and how it applies to any kind of intellectual property, be it a book, a song, or a photograph.
Considering the number of people who visit TPF daily (mostly non-members), it's a good place to reiterate that the vast majority of photographs, and other content online are copyrighted, and require permission from the copyright owner, to take and use.
However, you can
link to the same online material
all-day-long, and be both ethically and legally, safe and sound.