Hi and welcome to the ogre forums!
Yes, I went to the basic tutorial 3 and it indeed has image placeholders; unfortunately, it's been so long since I was on a quest to finish the tutorials I don't know if the image links have been broken or if new images are planned to be put in; On the other hand, you could probably complete the tutorial without them. What I would do in this case is run the code supplied with the tutorial:
http://www.ogre3d.org/tikiwiki/tiki-ind ... ial3Source
and see what is really happening there.
Also, just on a somewhat unrelated note: This forum is more geared toward basic programming questions; Not a problem at all, just mentioning it. Probably best place for this post would be the general discussion forum. Welcome again!