That picture was originally posted by Mike in the Despecialized Edition thread.
Here are the other images from the screening which he posted there:
Mike's original posts are in pages 122 and 123 of the thread. He explains more about the screening, how warm projector bulbs were in the 70s, and how the same print projected with modern lighting looks different:
http://originaltrilogy.com/FORUM/topic.cfm/Harmys-STAR-WARS-Despecialized-Edition-HD-AVCHD-DVD9-and-NTSC-DVD5-AVAILABLE-see-1st-post/topic/12713/page/122/
http://originaltrilogy.com/FORUM/topic.cfm/Harmys-STAR-WARS-Despecialized-Edition-HD-AVCHD-DVD9-and-NTSC-DVD5-AVAILABLE-see-1st-post/topic/12713/page/123/