iPhone 5s only has 1k photos on it, but iTunes says it has 3k photos

I'm running out of storage on my iPhone 5s (32 GB), and my photos are taking up the most GB. I only have 1k photos on my iPhone Camera Roll (as seen below), but iTunes says that my iPhone has 3k photos on it (also seen below).

I deleted the photos on my iPhone, then synced it with iTunes, but nothing changed. (Also, I do not have the iCloud Photo Library turned on.)

How do I delete those "photos" that iTunes says I have? Anything else I can do to get more storage?