commit b664d1fefd7140ec4ec37b3b90a9007839029d8a
Author: Tristan Stenner <ttstenner@gmail.com>
Date:   Fri Oct 9 08:40:04 2015 +0200

    Try tostring(), fall back to tobytes()

diff --git a/cropgtk.py b/cropgtk.py
index c1156b0..135b6a8 100755
--- a/cropgtk.py
+++ b/cropgtk.py
@@ -170,7 +170,11 @@ class DragManager(DragManagerBase):
             rendered = self.rendered()
             rendered = rendered.convert('RGB')
             i.set_size_request(*rendered.size)
-            pixbuf = gtk.gdk.pixbuf_new_from_data(rendered.tostring(),
+            try:
+                image_data = rendered.tostring()
+            except:
+                image_data = rendered.tobytes()
+            pixbuf = gtk.gdk.pixbuf_new_from_data(image_data,
                 gtk.gdk.COLORSPACE_RGB, 0, 8,
                 rendered.size[0], rendered.size[1], 3*rendered.size[0])
 
diff --git a/filechooser.py b/filechooser.py
index f2f8122..a039d74 100644
--- a/filechooser.py
+++ b/filechooser.py
@@ -49,7 +49,11 @@ def update_preview_cb(file_chooser, preview):
             i.thumbnail((PREVIEW_SIZE, PREVIEW_SIZE), Image.ANTIALIAS)
             i = i.convert('RGB')
             i = apply_rotation(r, i)
-            pixbuf = gtk.gdk.pixbuf_new_from_data(i.tostring(), 
+            try:
+                image_data = i.tostring()
+            except:
+                image_data = i.tobytes()
+            pixbuf = gtk.gdk.pixbuf_new_from_data(image_data, 
                 gtk.gdk.COLORSPACE_RGB, 0, 8, i.size[0], i.size[1],
                 i.size[0]*3)
             preview.set_from_pixbuf(pixbuf)