I watched all of "New Hope" along with the 2004 DVD (simultaneously) and it was very interesting to see the changes/ additions.
There's a wonderful set called the WookieGroomer Splits which have just what you've done, but they are nicely edited so you don't have to do the pause and restart.
...and there's more changes then you'd believe, this thread is documenting them:
But for the image you are looking for if this thread does yield results, try asking here:
http://originaltrilogy.com/forum/topic.cfm/HI-Res-Poster-Art/topic/2311/unread/1/