I have not done it But ...
http://java.sun.com/docs/books/tutorial/uiswing/components/table.html
States that an ImageIcon or Icon ? is rendered by a centered label. (default render)
So load the image to an imageIcon and put it in the data structure.
Searches find these - Looking quickly I see people seem to think it works.
http://search.sun.com/search/developers/index.jsp?and=imageicon+jtable+cell&nh=10&phr=&qt=¬=&field=&since=&col=devforums&rf=0&Search.x=21&Search.y=9
http://forum.java.sun.com/thread.jspa?forumID=257&threadID=112774
rykk