Front Porch Posts Not Contacting Porch Slab
Typically in cases like this you'll have cantilevered trusses in the roof system with an interior bearing point. The posts are entirely decorative (and hold the railing system). The biggest clue is the shape of the gable.
It's possible that only the one by the door is carrying a load. There could be a small beam there for the high front gable, but that's not likely. You'll need to peek into your attic to be sure, but considering the design and apparent age of the home it's a safe bet.