I have an iPhone 6S and Windows PCs. I do not sync photos between the iPhone and PCs. I have about 716MB of space occupied by photos "Synced from iTunes Library" that I cannot see on the iPhone, or have any way to delete them. These photos cannot be found in iCloud either. So this post did not resolve my issue: Some photos aren't displayed when iPhone connected to PC
I already deleted all of the photos in the Photos app, but I still have the 716MB occupied and have no way to get rid of it. What do I do?