Intellectual Property Rights is very simple to understand, if you didn't make it then its not yours, the person who created the media / property will have at the very basic level artistic copyright.
If you have a site that does not mention copyright, do not assume that it does not exist because it will.
As NogDog suggests, seek permission or an agreement like you would with reproduction of media from another source. Take Yahoo, they do not create much, if any, news but reprint / produce its content from other news sources / services and they will do so because they have a reprint agreement with those specific agencies.
The internet has never been a "Free for all" that it is perceived to be yet most people treat the digital frontier exactly as such, somewhere you can do as you please.