diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..225c381
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.png
+*.jpg
diff --git a/README.md b/README.md
index b30296e..e819d75 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,11 @@ Options:
                                   capture.
   -f, --filename TEXT             Filename to save the captured PNG as.
   -a, --all_windows               Capture all windows matching parameters
+  -t, --type TEXT                 Image format to create, default is png
+                                  (other options include pdf, jpg, tiff)
+  -i, --interval INTEGER          Capture interval in seconds. Do not
+                                  duplicate similar images
+  -o, --no_shadow                 Do not capture the shadow of the window.
   --help                          Show this message and exit.
 ```
 
diff --git a/screencapture.py b/screencapture.py
index a87cc67..ba53b90 100755
--- a/screencapture.py
+++ b/screencapture.py
@@ -1,5 +1,9 @@
-#!/usr/bin/python3
-
+#!/Library/Frameworks/Python.framework/Versions/3.6/bin/python3
+import os
+import tempfile
+import time
+import imagehash as imagehash
+from PIL import Image
 from itertools import chain
 from datetime import datetime
 from subprocess import getstatusoutput
@@ -8,9 +12,8 @@
 
 from get_window_id import gen_window_ids, options, user_options_str
 
-
-FILE_EXT = '.png'
-COMMAND = 'screencapture -l %s "%s"'
+TOLERANCE = 3
+COMMAND = 'screencapture %s -l %s "%s"'
 STATUS_OK = 0
 
 
@@ -18,8 +21,9 @@ class ScreencaptureEx(Exception):
     pass
 
 
-def take_screenshot(window: int, filename: str, **kwargs) -> str:
-    rc, output = getstatusoutput(COMMAND % (window, filename))
+def take_screenshot(opts: str, window: int, filename: str, **kwargs) -> str:
+    command = COMMAND % (' '.join(opts), window, filename)
+    rc, output = getstatusoutput(command)
 
     if rc != STATUS_OK:
         raise ScreencaptureEx("Error in screenccapture command '%s'; Return code: %s Output: %s" % (COMMAND, rc, output))
@@ -27,8 +31,8 @@ def take_screenshot(window: int, filename: str, **kwargs) -> str:
     return filename
 
 
-def _filename(*args) -> str:
-    return '_'.join(map(str, args + (datetime.now(),))) + FILE_EXT
+def _filename(file_ext: str, *args) -> str:
+    return '_'.join(map(str, args + (datetime.now(),))) + file_ext
 
 
 @click.command()
@@ -37,9 +41,39 @@ def _filename(*args) -> str:
 @click.option('-t', '--title', default='', help="Title of window from APPLICATION_NAME to capture.")
 @click.option('-f', '--filename', default=None, help="Filename to save the captured PNG as.")
 @click.option('-a', '--all_windows', is_flag=True, default=False, help="Capture all windows matching parameters.")
+@click.option('-t', '--type', default=None,
+              help="Image format to create, default is png (other options include pdf, jpg, tiff)")
+@click.option('-i', '--interval', default=0, help="Capture interval in seconds. Do not duplicate similar images")
+@click.option('-o', '--no_shadow', is_flag=True, default=False, help="Do not capture the shadow of the window.")
 @click.argument('application_name')
-def screenshot_window(application_name: str, title: str='', filename: str='', window_selection_options: str='',
-                      all_windows: bool=False, **kwargs):
+def screenshot_window(application_name: str,
+                      title: str = '',
+                      filename: str = '',
+                      window_selection_options: str = '',
+                      all_windows: bool = False,
+                      interval: int = None,
+                      no_shadow: bool = False,
+                      type: str = 'png',
+                      **kwargs):
+
+    opts = []
+    file_ext = '.png'
+
+    if no_shadow:
+        opts.append("-o")
+
+    if type == 'jpg':
+        opts.append("-t jpg")
+        file_ext = '.jpg'
+
+    if type == 'tiff':
+        opts.append("-t tiff")
+        file_ext = '.tiff'
+
+    if type == 'pdf':
+        opts.append("-t pdf")
+        file_ext = '.pdf'
+
     windows = gen_window_ids(application_name, title, window_selection_options)
 
     try:
@@ -52,12 +86,32 @@ def screenshot_window(application_name: str, title: str='', filename: str='', wi
         windows = chain((window,), windows)
 
         for window in windows:
-            filename = _filename(application_name, title)
-            print(take_screenshot(window, filename))
-
-    else:
-        filename = filename if filename else _filename(application_name, title)
-        print(take_screenshot(window, filename))
+            filename = _filename(file_ext, application_name, title)
+            print(take_screenshot(opts, window, filename))
+        exit()
+
+    if interval > 0:
+        prev_hash = ''
+        while True:
+            base_filename = _filename(file_ext, application_name, title)
+            temp_filename = "%s/%s" % (tempfile.gettempdir(), base_filename)
+
+            take_screenshot(opts, window, temp_filename)
+
+            if os.path.isfile(temp_filename):
+                image_hash = imagehash.average_hash(Image.open(temp_filename))
+                if not prev_hash or abs(prev_hash - image_hash) > TOLERANCE:
+                    os.rename(temp_filename, base_filename)
+                    print("Captured %s" % base_filename)
+                    prev_hash = image_hash
+                else:
+                    os.remove(temp_filename)
+
+            time.sleep(interval)
+        exit()
+
+    filename = filename if filename else _filename(file_ext, application_name, title)
+    print(take_screenshot(opts, window, filename))
 
 
 if __name__ == "__main__":