There is no photo limit for listings on Trulia. I recommend that you contact the feed providers you mentioned in your email to ensure that they are indeed sending all of your photos to us. Our Customer Service team can check that as well, however if they find that photos are missing from these feeds, you will need to contact the feed providers to make sure they add those missing photos.
Also, please note that you can manually upload photos on Trulia at your convenience. If those listings are already associated with your My Trulia account, just visit your My Listings page and select the option to 'Edit listing details'. You'll then see the option to edit your listing photos.
I hope this helps you. If you have any other questions or feedback for us, please let us know.