For the before picture, I cropped out an image of my pudgy tummy from the swim exit during a triathlon last September and stuck it up in the upper right corner. The "after" photo is from a few days ago.
I realize it's not really an apples to apples comparison, so to a certain extent you will simply have to trust me on this - I'm seeing less pudginess (probably due to diet changes) and more definition (probably from the ab work).
As for the challenge itself, I had agreed to use "strength improvement" as my measure of success. I'm still planning to do that.
In any event, I'm motivated to keep working on my abs at the same level of intensity. Who knows, maybe I'll even post another photo a month from now...