Your listings will automatically display the photo you have on your Trulia profile, however at present you don't appear to have a profile photo. To add one, access the link below to navigate to your profile page. Then, select the link on the left to 'Edit Profile'. On the next page you'll see the option to upload a photo under your current profile image.
Upload the photo you'd like to see on your listings and you should see it display shortly after.
Let us know if you experience any difficulties with this process.