If the agent or the mls is registered with Listhub.com all MLS listings are sent to 50 internet sites 3-5 times a day. Trulia, Realtor.com, Zillow and 47 others get updated several times a day. You can ask your agent if they use Listhub or if their MLS sends listings to Trulia. if not Trulia also allows agents to enter listings and they also grab listings from other sources including public data sites like from your county. It could have come from any number of sources, the public data would be my guess as many photos they use can be pretty poor.