Howdy, partner. It seems that the quality of the images used on this page ain't quite what we expected. You could definitely help out the wiki by uploading some. If you're logged in, it'll get you some achievements going.
He can also be seen wandering the streets of Armadillo, where he often pins up the wanted posters on the train station and then continues to patrol. When Marston brings live bounty to Armadillo jail, he assists with the transfer of the criminal. However, if Marston has a bounty, Alden will track him to multiple locations around New Austin.