import praw
import urllib
import cv2, numpy as np

DOWNSCALE = 2

r = praw.Reddit('/u/powderblock Glasses Bot')

foundImage = False
 
for post in r.get_subreddit('all').get_new(limit=15):
        if "imgur.com" in post.url and (".jpg" in post.url or ".png" in post.url):
                        print str(post.url)
                        foundImage = True
                        break

if foundImage:
        urllib.urlretrieve(str(post.url), "image.jpg")
        # load the image we want to detect features on
        frame = cv2.imread('image.jpg')
        minisize = (frame.shape[1]/DOWNSCALE,frame.shape[0]/DOWNSCALE)
        miniframe = cv2.resize(frame, minisize)
        cv2.imshow("Loading Images From a Buffer From a URL", miniframe)

        while True:
            # key handling (to close window)
            key = cv2.waitKey(20)
            if key in [27, ord('Q'), ord('q')]: # exit on ESC
                cv2.destroyWindow("Facial Features Test")
                break
if not foundImage:
        print("No Image found.")

import praw
import urllib
r = praw.Reddit('/u/powderblock Glasses Bot')

for post in r.get_subreddit('all').get_new(limit=5):
        if "imgur.com" in post.url and (".jpg" in post.url or ".png" in post.url):
                        print str(post.url)
                        urllib.urlretrieve(str(post.url), "image.jpg")

--- 
+++ 
@@ -1,8 +1,32 @@
 import praw
 import urllib
+import cv2, numpy as np
+
+DOWNSCALE = 2
+
 r = praw.Reddit('/u/powderblock Glasses Bot')
 
-for post in r.get_subreddit('all').get_new(limit=5):
+foundImage = False
+ 
+for post in r.get_subreddit('all').get_new(limit=15):
         if "imgur.com" in post.url and (".jpg" in post.url or ".png" in post.url):
                         print str(post.url)
-                        urllib.urlretrieve(str(post.url), "image.jpg")
+                        foundImage = True
+                        break
+
+if foundImage:
+        urllib.urlretrieve(str(post.url), "image.jpg")
+        # load the image we want to detect features on
+        frame = cv2.imread('image.jpg')
+        minisize = (frame.shape[1]/DOWNSCALE,frame.shape[0]/DOWNSCALE)
+        miniframe = cv2.resize(frame, minisize)
+        cv2.imshow("Loading Images From a Buffer From a URL", miniframe)
+
+        while True:
+            # key handling (to close window)
+            key = cv2.waitKey(20)
+            if key in [27, ord('Q'), ord('q')]: # exit on ESC
+                cv2.destroyWindow("Facial Features Test")
+                break
+if not foundImage:
+        print("No Image found.")
Save Image to File, Open Image if found

Add image checking using urllib and opencv.
