diff -Nru a/cal3d/model.pyx b/cal3d/model.pyx
--- a/cal3d/model.pyx	2008-07-27 12:36:00.000000000 +0200
+++ b/cal3d/model.pyx	2016-08-29 08:17:28.532373042 +0200
@@ -47,7 +47,7 @@
 	for y from 0 <= y < height:
 		data2[y * line_length : (y + 1) * line_length] = data[(height - y - 1) * line_length : (height - y) * line_length]
 		
-	return Image(data2.tostring(), width, height, nb_colors)
+	return Image(data2.tobytes(), width, height, nb_colors)
 
 def parse_cal3d_cfg_file(filename):
 	"""Reads a the Cal3D .cfg file, and creates and returns a Cal3D model from it."""
diff -Nru a/model/image.pyx b/model/image.pyx
--- a/model/image.pyx	2009-04-25 23:44:40.000000000 +0200
+++ b/model/image.pyx	2016-08-29 08:20:40.106907620 +0200
@@ -43,7 +43,7 @@
 		image.nb_color = 1 
 		image.palette = pil_image.palette.palette
 	else: raise ValueError("unknown image mode (%s)" % pil_image.mode)
-	image.pixels = pil_image.tostring()
+	image.pixels = pil_image.tobytes()
 	return image
 
 def screenshot(filename = None, int x = 0, int y = 0, int width = 0, int height = 0, use_back_buffer=False):