same goes for most of social network apps like ig etcFor those on 16gb and wanna squeeze every drop of memory. U can check the Facebook app memory size in the storage manager then delete Facebook and reinstall again. U will see that u will get back additional hundreds of MB.
Facebook apps store the cache/cookie in your phone. Reinstall will delete these Data and free the memory. Repeat the step of u think it is taking up too much memory
upload all photos to google photos
delete all photos on phone....
