Can an image from a paper by author A be used in a published book by author B? Generally, is it acceptable for one author to use an image, or video, from another author's paper in a book, provided that the original author is credited. 

For example, I'd like to write something to the following effect. 


  Jekyl &amp; Hyde instructed a set of subjects to rate the attractiveness
  of each of the following two 3D-rendered animations of human dance. 
  [VIDEO 1] [VIDEO 2]...


There are some important, and unique, images that convey information that can't be concisely described. I'm concerned that my requests to use the images might be ignored (I figure that answering a request from an unknown person from a distant university would be pretty low priority for most busy people), and that consequently, I wouldn't be able to effectively convey the author's findings to the reader.
Check what licences apply to the paper by author A. In particular, look at the top left-hand corner of the first page of the paper. If it says (c) the publisher, then you'll have to check with the publisher. If it says (c) the authors, then there's a good chance one of the creative commons licenses apply.