diff --git a/fsl/data/image.py b/fsl/data/image.py
index 5dc297b924d5152420a6a52c6a5c2e705521edd7..755037cab0a8c1263b81ef0bf58eefe8bd89ab4c 100644
--- a/fsl/data/image.py
+++ b/fsl/data/image.py
@@ -827,7 +827,7 @@ def loadIndexedImageFile(filename):
     fobj = igzip.SafeIndexedGzipFile(
         filename=filename,
         spacing=4194304,
-        readbuf_size=131072)
+        readbuf_size=1048576)
 
     fmap = nib.Nifti1Image.make_file_map()
     fmap['image'].fileobj = fobj
diff --git a/fsl/data/imagewrapper.py b/fsl/data/imagewrapper.py
index b05510d8aa493b3060f7147a921a8741f09ea945..2e7ab6ac672b65b807fb3476b7e2833cd68ffc8a 100644
--- a/fsl/data/imagewrapper.py
+++ b/fsl/data/imagewrapper.py
@@ -12,7 +12,7 @@ Terminology
 -----------
 
 
-There are some confusing terms used in this module, so it may be of use to
+There are some confusing terms used in this module, so it may be useful to
 get their definitions straight:
 
   - *Coverage*:  The portion of an image that has been covered in the data
diff --git a/fsl/utils/dialog.py b/fsl/utils/dialog.py
index 3228ae612c66842840d9742b7ea0185d22765b74..274ca6873186960939f31c2d7e07c048d50b1157 100644
--- a/fsl/utils/dialog.py
+++ b/fsl/utils/dialog.py
@@ -22,6 +22,7 @@ import            os
 import os.path as op
 import            threading
 
+import            six
 import            wx
 
 from .platform import platform as fslplatform
@@ -671,7 +672,25 @@ class FSLDirDialog(wx.Dialog):
         self.__contentSizer.Add(self.__message, flag=wx.EXPAND, proportion=1)
         self.__contentSizer.Add((1, 20))
         self.__contentSizer.Add(self.__buttonSizer, flag=wx.EXPAND)
-        
+
+        # If running on OSX, add a message
+        # telling the user about the
+        # cmd+shift+g shortcut
+        if fslplatform.os == 'Darwin':
+
+            self.__hint = wx.StaticText(
+                self,
+                label=six.u('Hint: Press \u2318+\u21e7+G in the file '
+                            'dialog to manually type in a location.'))
+
+            self.__hint.SetForegroundColour('#888888')
+
+            self.__contentSizer.Insert(2, self.__hint, flag=wx.EXPAND)
+            self.__contentSizer.Insert(3, (1, 20))
+            
+        else:
+            self.__hint = None
+            
         self.__mainSizer.Add(self.__icon,
                              flag=wx.ALL | wx.CENTRE,
                              border=20)