Roughly removing 'duplicate' photos based on filename
If you're only dealing with only .jpg files then it will be better to use the glob module:

import glob

for filepath in glob.iglob(os.path.join(directory), '*.jpg'):
   ...


Don't use dict.keys() to check for the existence of a key in dictionary, it is inefficient in Python 2(created a whole list first and then searches for key in that list) and requires an unnecessary call to .keys() in Python 3. Or even better use collections.Counter to keep counts of objects:

from collections import Counter

dt_counter = Counter()

for filepath in glob.iglob(os.path.join(directory), '*.jpg'):
    dt_rounded = os.path.split(filepath)[1][:16]
    dt_counter[dt_rounded] += 1
    if dt_counter[dt_rounded] &gt; 1:
         # if `directory` is actually a `pathToPhotos` then you 
         # don't need to call os.path.join anymore
         os.remove(filepath)