You can get to most of the random title photos just by pressing the refresh button (backwards green arrow). On the way you will get lots of repetitions, and even after 200 presses there is a strong chance that one has remained elusive. It used to be a straight classroom probability exercise.
There are now about 100 photos in the pool.
If you want one particular photo, pr(success) = 1/100 = 0.01
pr(failure) = 0.99
pr (100 consecutive failures) = 0.99^100 = 0.36, which is still fairly high.
pr (200 consecutive failures) = 0.13, which is still fairly high.
pr (300 consective failures) = 0.05, which is 1 in 20.
In this instance it is probably my photo of the Posadas (Argentina) to Encarnacion (Paraguay) crossing, taken in Jan.85. Already, a bridge was under construction, and had replaced the ferries by my 1995 visit.
There is a quite a lot about these in various postings: searching on Posadas should get there, then you get the names, then you can search on the rest of the posts.
Roderick B Smith
Rail News Victoria Editor