diff --git a/lib/matplotlib/backends/backend_pgf.py b/lib/matplotlib/backends/backend_pgf.py
index fa5e520b617f..9b7f0906eb4a 100644
--- a/lib/matplotlib/backends/backend_pgf.py
+++ b/lib/matplotlib/backends/backend_pgf.py
@@ -18,7 +18,6 @@
     _Backend, FigureCanvasBase, FigureManagerBase, GraphicsContextBase,
     RendererBase)
 from matplotlib.backends.backend_mixed import MixedModeRenderer
-from matplotlib.cbook import is_writable_file_like
 from matplotlib.path import Path
 from matplotlib.figure import Figure
 from matplotlib._pylab_helpers import Gcf
@@ -385,8 +384,8 @@ def __init__(self, figure, fh, dummy=False):
             Matplotlib figure to initialize height, width and dpi from.
         fh : file-like
             File handle for the output of the drawing commands.
-
         """
+
         RendererBase.__init__(self)
         self.dpi = figure.dpi
         self.fh = fh
@@ -842,16 +841,10 @@ def print_pgf(self, fname_or_fh, *args, **kwargs):
         if kwargs.get("dryrun", False):
             self._print_pgf_to_fh(None, *args, **kwargs)
             return
-
-        # figure out where the pgf is to be written to
-        if isinstance(fname_or_fh, str):
-            with open(fname_or_fh, "w", encoding="utf-8") as fh:
-                self._print_pgf_to_fh(fh, *args, **kwargs)
-        elif is_writable_file_like(fname_or_fh):
-            fh = codecs.getwriter("utf-8")(fname_or_fh)
-            self._print_pgf_to_fh(fh, *args, **kwargs)
-        else:
-            raise ValueError("filename must be a path")
+        with cbook.open_file_cm(fname_or_fh, "w", encoding="utf-8") as file:
+            if not cbook.file_requires_unicode(file):
+                file = codecs.getwriter("utf-8")(file)
+            self._print_pgf_to_fh(file, *args, **kwargs)
 
     def _print_pdf_to_fh(self, fh, *args, **kwargs):
         w, h = self.figure.get_figwidth(), self.figure.get_figheight()
@@ -896,21 +889,12 @@ def _print_pdf_to_fh(self, fh, *args, **kwargs):
                 TmpDirCleaner.add(tmpdir)
 
     def print_pdf(self, fname_or_fh, *args, **kwargs):
-        """
-        Use LaTeX to compile a Pgf generated figure to PDF.
-        """
+        """Use LaTeX to compile a Pgf generated figure to PDF."""
         if kwargs.get("dryrun", False):
             self._print_pgf_to_fh(None, *args, **kwargs)
             return
-
-        # figure out where the pdf is to be written to
-        if isinstance(fname_or_fh, str):
-            with open(fname_or_fh, "wb") as fh:
-                self._print_pdf_to_fh(fh, *args, **kwargs)
-        elif is_writable_file_like(fname_or_fh):
-            self._print_pdf_to_fh(fname_or_fh, *args, **kwargs)
-        else:
-            raise ValueError("filename must be a path or a file-like object")
+        with cbook.open_file_cm(fname_or_fh, "wb") as file:
+            self._print_pdf_to_fh(file, *args, **kwargs)
 
     def _print_png_to_fh(self, fh, *args, **kwargs):
         converter = make_pdf_to_png_converter()
@@ -933,20 +917,12 @@ def _print_png_to_fh(self, fh, *args, **kwargs):
                 TmpDirCleaner.add(tmpdir)
 
     def print_png(self, fname_or_fh, *args, **kwargs):
-        """
-        Use LaTeX to compile a pgf figure to pdf and convert it to png.
-        """
+        """Use LaTeX to compile a pgf figure to pdf and convert it to png."""
         if kwargs.get("dryrun", False):
             self._print_pgf_to_fh(None, *args, **kwargs)
             return
-
-        if isinstance(fname_or_fh, str):
-            with open(fname_or_fh, "wb") as fh:
-                self._print_png_to_fh(fh, *args, **kwargs)
-        elif is_writable_file_like(fname_or_fh):
-            self._print_png_to_fh(fname_or_fh, *args, **kwargs)
-        else:
-            raise ValueError("filename must be a path or a file-like object")
+        with cbook.open_file_cm(fname_or_fh, "wb") as file:
+            self._print_png_to_fh(file, *args, **kwargs)
 
     def get_renderer(self):
         return RendererPgf(self.figure, None, dummy=True)
diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
index e935ceed2bad..258884157b27 100644
--- a/lib/matplotlib/cbook/__init__.py
+++ b/lib/matplotlib/cbook/__init__.py
@@ -360,14 +360,14 @@ def is_hashable(obj):
 
 
 def is_writable_file_like(obj):
-    """return true if *obj* looks like a file object with a *write* method"""
+    """Return whether *obj* looks like a file object with a *write* method."""
     return callable(getattr(obj, 'write', None))
 
 
 def file_requires_unicode(x):
     """
-    Returns `True` if the given writable file-like object requires Unicode
-    to be written to it.
+    Returns whether the given writable file-like object requires Unicode to be
+    written to it.
     """
     try:
         x.write(b'')
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
index 65fa77ea9070..b6491ba3f41f 100644
--- a/lib/matplotlib/image.py
+++ b/lib/matplotlib/image.py
@@ -730,9 +730,7 @@ def set_interpolation(self, s):
         self.stale = True
 
     def can_composite(self):
-        """
-        Returns `True` if the image can be composited with its neighbors.
-        """
+        """Return whether the image can be composited with its neighbors."""
         trans = self.get_transform()
         return (
             self._interpolation != 'none' and
@@ -741,11 +739,12 @@ def can_composite(self):
 
     def set_resample(self, v):
         """
-        Set whether or not image resampling is used.
+        Set whether image resampling is used.
 
         Parameters
         ----------
-        v : bool
+        v : bool or None
+            If None, use :rc:`image.resample` = True.
         """
         if v is None:
             v = rcParams['image.resample']
@@ -753,7 +752,7 @@ def set_resample(self, v):
         self.stale = True
 
     def get_resample(self):
-        """Return the image resample boolean."""
+        """Return whether image resampling is used."""
         return self._resample
 
     def set_filternorm(self, filternorm):