Add Thumbnail generator

This is multithreaded and will almost probably crash your machine if
you give it a large folder to generate thumbnails for at once.

Also generates a file `pathlist.txt` that contains the publically
accessible URLs for all images that were indexed (For feeding into the
layout generator)

baseuri is the public s3 url
s3_path is where you have your images stored (can be any FS)
browse_path is folders inside your s3_path
thumb_path is where to store the generated thumbnails
thumbsize is how big in pixels the thumbnails should be

GenThumb.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+# GenThumb.py - Part of the simple s3 gallery
+# Usage: ./GenThumb.py
+
+from pathlib import Path
+from PIL import Image
+import logging
+import _thread
+import time
+
+logging.basicConfig(filename='GenThumb.log', level=logging.DEBUG,
+                    format='%(asctime)s [%(levelname)s] %(message)s',
+                    datefmt='%m/%d/%Y %I:%M:%S %p')
+logging.info("---------------")
+
+baseuri = "https://s3.wasabisys.com/c0de-photography/"
+s3_path = "/mnt/photos/"
+browse_path = "EOS M100/"
+thumb_path = "./thumbs"
+thumbsize = (250, 250)
+
+
+logging.info("Getting Paths (Can take time on large directories)")
+filelist = list(Path(s3_path + browse_path).rglob("*.[jJ][pP][gG]"))
+thumblist = list(Path(thumb_path).rglob("*.[jJ][pP][gG]"))
+
+def gen_thumb(image):
+    imagepath = "%s" % image.parent
+    imagepath = imagepath.strip(s3_path)
+    pathlist.write(baseuri + imagepath + image.name)
+    thumbname = "%s/%s:%s" % (thumb_path, imagepath, image.name)
+
+    if image.name in "%s" % thumblist:
+        logging.debug("Skipping %s" % image)
+    else:
+        logging.info("Generating thumbnail for New Image: %s" % (image))
+
+        img = Image.open(image)
+        img.thumbnail(thumbsize)
+        img.save(thumbname)
+
+        logging.info("Saved Thumbnail as %s" % thumbname)
+
+with open('pathlist.txt', 'w') as pathlist:
+    for image in filelist:
+        try:
+            _thread.start_new_thread(gen_thumb, (image,))
+            time.sleep(0.15)
+        except:
+            logging.error("unable to start thread")
+
+logging.info("Wait for all threads to save")
+
+while(1):
+    pass
+