Spent 6 weeks tracing a fake moon landing photo back to a 1997 stock photo

I was digging through an old conspiracy forum thread about the Apollo 11 pics and someone posted a 'smoking gun' image that supposedly proved the whole thing was staged. The lighting looked off to me, so I did a reverse image search and found the exact same crater shot in a 1997 NASA educational CD-ROM. Took me about 6 weeks of on and off searching because the file name had been changed and the metadata stripped. I finally matched it by comparing the shadow angles pixel by pixel in GIMP with a free online tool. The person who posted it never replied when I called them out, just deleted their account. Has anyone else actually tracked down the origin of a 'proof' image and had it turn out to be recycled footage or photos? What was your longest rabbit hole?