My iPhone says I have more photos and videos than i have.

i have a problem with my iphone, i have only 893 photos and 19 videos in the photo library, but in settings > general > about said that i have 1813 photos, 57 videos, and it's taking up 5.2GB of data on my 16 GB phone. I cleared the "Recently deleted" album and deleted stuff from there, but it didn't make a difference to the 5.2 GB of supposed stored photos. What do i do? where or what are the other 920 photos, 38 videos, and how can i fix them?