When your listing expired in February, that listing only indicated 3949 square feet.
Was it measured by a licensed appraiser for that listing? Did that include your finished attic?
Have you had it measured by a licensed appraiser to support the 4000 square foot claim?
A mentioned, to update the photos, you will need to be on MLS, as Trulia sweeps listing details from MLS and from agents.
Also, you should bear in mind that Trulia is not a great venue for advertising homes to actually sell them. Trulia is for agents to troll ads to catch potential clients.
Trulia should be an afterthought, not a cornerstone of an aggressive advertising campaign.