It can display images, but I agree that it isn't displaying any from the World Fact eBook. See for example Poe, Edgar Allan: The Raven (ill) by Dore. v1. 22 Jan 2009
, or any of the illustrated examples in the MOBI library.
In FBReader the images are always centered, and if they are too big to show they will be clipped to the screen.
Note that FBReader will also display HTML (and it also fails to display images in the HTML extracted from the World Fact eBook). I tried to extract France (with its map) as a stand-alone HTML test, but the text isn't very editor friendly.