There is no definite yes or no answer to this. It depends on when and where the material was published and for what purpose and also where in the world you're looking at it. At the moment, there is no way to prevent any image, sound, film or text that appears anywhere on the web from being copied and reproduced. What you need to consider is that, if you post anything, you personally will be liable if someone decides to sue or invoice you for its use.
In practice, if you publish a few pictures from a magazine or an article, it is very unlikely that anyone will take exception as long as you very clearly credit where you got it from and you or Rumcars aren't trying to profit financially from it. It is good etiquette to contact the originator of the work to try and obtain permission beforehand, but as much of the stuff we're interested in is from obscure or long extinct sources, you'll probably end up chasing your tail. Regardless, whatever the published origin, give it the credit it deserves.
In regard to more current material, in my experience, informally for a venue like our forum, editors are usually happy for you to post the material. It gives them more publicity which in turn might result in a few more sales. However, formally they'll have to quote corporate policy, which is likely to say yes of course you may reproduce the article on your website, here is our bill for £XXXs. If in doubt, tell people where they can buy a copy of this great article you've seen.
Treat other peoples work with the same respect, care, due credit and consideration, you'd expect for your own work and hopefully everyone will benefit.