I'm afraid that Scott's answer is not entirely correct. Only listings that have been manually submitted to us can be edited in the manner he described.
I believe you are referring to the listing shown at the link below. We currently receive this listing information from coloradohomes.com and they don't include a photo for this property in the data feed they send to us. Your best option would be to contact coloradohomes.com to ensure that they add the listing photo to this data feed. Once they do so, the listing information on Trulia will update automatically to show the new image.
Customer Service Representative