Google: Python natural sorting.
Result 1: The page you linked to.
But don’t stop there!
Result 2: Jeff Atwood’s blog that explains how to do it properly.
Result 3: An answer I posted based on Jeff Atwood’s blog.
Here’s the code from that answer:
import re
def natural_sort(l):
convert = lambda text: int(text) if text.isdigit() else text.lower()
alphanum_key = lambda key: [convert(c) for c in re.split('([0-9]+)', key)]
return sorted(l, key=alphanum_key)
Results for your data:
PresserInc-1.jpg PresserInc-1_10.jpg PresserInc-1_11.jpg PresserInc-2.jpg PresserInc-3.jpg etc...
See it working online: ideone