diff --git a/addons/hw_escpos/escpos/escpos.py b/addons/hw_escpos/escpos/escpos.py
index d35da17412f..bb60d632e96 100644
--- a/addons/hw_escpos/escpos/escpos.py
+++ b/addons/hw_escpos/escpos/escpos.py
@@ -439,11 +439,11 @@ class Escpos:
             img_rgba = Image.open(f)
             img = Image.new('RGB', img_rgba.size, (255,255,255))
             channels = img_rgba.split()
-            kwargs = {}
             if len(channels) > 1:
                 # use alpha channel as mask
-                kwargs['mask'] = img_rgba.split()[3]
-            img.paste(img_rgba, **kwargs)
+                img.paste(img_rgba, mask=channels[3])
+            else:
+                img.paste(img_rgba)
 
             print 'convert image'