One application of this I can see is to create a page like this to understand what sites your company's (or country's) firewall / proxy might be blocking.
Might be even a little easier for an end user if you wrote some javascript that just showed the appropriate message. If the pictures won't load, just have a big "You Are Safe." message. Making people look at the pictures isn't actually needed.
I disagree. This requires absolutely no technical skill to interpret, and yet they haven't abstracted away the evidence.
I am much more reassured by this, then I would be with some website that said "You Are Safe". Presenting the user with the evidence that they are safe is much more reassuring than just saying "You Are Safe, trust us on this one, we know what we're talking about."