I have been very careful with pictures - the one who has taken the photo owns the rights and nobody should use pictures from web without the approval of the originator. There's one exception: Creative Commons licensed pictures in Flickr. Do you know if there are same kind of licenses in other systems too?
Video copyrights were a mystery for me so far but I got advice from a forum guru and he told that it is safe you use embedded YouTube videos in forums so I started to add them to the wiki.
See e.g. Titania's palace or Queen Mary's dollhouse.
I like also the videos made by MiniMaker07, see e.g. the Victorian dollhouse in this page.
So if you find nice YouTube videos please add them to the wiki.