By the way, you can test whether the regular expression matches without getting Django involved, allowing for much quicker theories and tests.
$ python
Python 2.7.3 (default, Jun 9 2014, 04:37:23)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> re.match(r'^(?P<path>(?:js|css|img)/.*)$', 'css/style.css')
<_sre.SRE_Match object at 0x7fb34977ddc8>
>>> _.groups()
('css/style.css',)
>>> re.match(r'^(?P<path>(?:js|css|img)/.*)$', 'apps/css/style.css') # Does not match
>>> re.match(r'^(?P<path>(?:js|css|img)/.*)$', 'apps/another.html') # Does not match
>>> re.match(r'^(?P<path>(?:apps|js|css|img)/.*)$', 'apps/another.html')
<_sre.SRE_Match object at 0x7fb34977ddc8>
>>> _.groups()
('apps/another.html',)
>>>