diff --git a/oxtimelines/timeline.py b/oxtimelines/timeline.py
index dbba494..30cbf25 100644
--- a/oxtimelines/timeline.py
+++ b/oxtimelines/timeline.py
@@ -2,7 +2,7 @@
 # vi:si:et:sw=4:sts=4:ts=4
 # GPL 2008-2012
 
-from __future__ import division
+from __future__ import division, with_statement
 
 from glob import glob
 import Image
@@ -321,11 +321,12 @@ class Timelines():
         #remove tiles that might exist from previous run
         if not self.points:
             for mode in self.modes:
-                tiles = glob('%s/timeline%s*%d*.jpg' % (self.tile_path, mode, self.large_tile_h))
+                type = 'png' if mode == 'data' else 'jpg'
+                tiles = glob('%s/timeline%s*%d*.%s' % (self.tile_path, mode, self.large_tile_h, type))
                 for f in ox.sorted_strings(tiles)[self.large_tile_i+2:]:
                     os.unlink(f)
                 if self.render_small_tiles:
-                    tiles = glob('%s/timeline%s*%d*.jpg' % (self.tile_path, mode, self.small_tile_h))
+                    tiles = glob('%s/timeline%s*%d*.%s' % (self.tile_path, mode, self.small_tile_h, type))
                     for f in ox.sorted_strings(tiles)[self.small_tile_i+2:]:
                         os.unlink(f)
 
@@ -526,7 +527,7 @@ class Timelines():
 
     def _open_full_tile(self):
         if self.large_tile_n == 1:
-            self.full_tile_widhts = [self.large_tile_last_w]
+            self.full_tile_widths = [self.large_tile_last_w]
         else:
             full_tile_w = self.full_tile_w
             full_tile_n = self.large_tile_n
@@ -629,11 +630,10 @@ class Timelines():
                 if self.cuts_path:
                     # remove cuts at max_cut_len
                     self.cuts = filter(lambda x: x not in self.no_cuts, self.cuts)
-                    f = open(self.cuts_path + 'cuts.json', 'w')
-                    # remove 0 and frame_n from cuts
-                    # avoid float rounding artefacts
-                    f.write('[' + ', '.join(map(lambda x: '%.2f' % (x / FPS), self.cuts[1:-1])) + ']')
-                    f.close()
+                    with open(self.cuts_path, 'w') as f:
+                        # remove 0 and frame_n from cuts
+                        # avoid float rounding artefacts
+                        f.write('[' + ', '.join(map(lambda x: '%.2f' % (x / FPS), self.cuts[1:-1])) + ']')
             if self.render_audio:
                 self._render_audio(self.volume)
             if self.log: