Thread:Forum:Tech Wishlist And Bug Reports/Question on importing images from Wikipedia/Wikimedia Commons

How do I import images (preferably, of course, those under CC-BY-SA, Fair Use, and similar licenses) from Wikipedia and Wikimedia Commons? I've been having problems trying to import some images from those places, namely I don't know the first thing about importing images. I could honestly use some advice/help on this. Thank you!