Allright guys, let me clear this up for you. As we all know, the Recipe for creating Intrigue card art is as follows:
1. Depict the thing the card actually names.
2. Add two people acting suspicious.
Unlike Wishing Well, Shanty Town, Nobles and Baron, Trading Post only has one visible person acting suspicious, which explains why all of you are confused. What you are missing is that the other person is simply very well hidden, and that THIS is where the actual Intrigue lies. I must say i'm disappointed that none of you got this obvious fact. I mean, really, when will you stop falling for troll posts with over-the-top theories like "He's going to rob the Trading Post"?