jim_carson: After a 10 year run, and this is getting vandalized more, it's time to retire this one. I will retrieve what's left this weekend or after the river of rain passes, whichever comes last.
How to solve: As alluded to by the SMBC cartoon, background image and related web page, this is a trilateration problem. Each photo depicts a position -- New York Cupcakes, Starbucks, Blazing Bagels (clearly I am a cache-to-eat person) -- and a distance. If you draw a circle around each position, using the accuracy measurement as the radius, the intersection is the location of the cache.
There are a variety of ways to do the calculation including GSAK (RIP), Garmin Basecamp, Excel, online tools. Because each can result in rounding error, I had a pretty big range for the solution checker.
Thanks to folks for the wonderful comments and favorite points, and to Geocaching.Com for continuously improving (and at least two rewrites) of the phone app to make it indispensable. On a recent trip, I was able to accomplish a few hundred finds in eastern CO/western KS using my phone.