There's a strong possibility that the slow upload of your photos has nothing to do with Trulia, and more to do with the size of the photos that were uploaded.
Photos have to be optimized for view online, and it sounds as though they haven't been. Discuss with your agent.
Your photos loading slowly is not causing you to miss the selling season. Trulia is a "national" (actually international) website... it's typically your local marketing that sells your home... internet advertising is great... but nothing can surpass what your local agent can do... that's where buyers are.