Set a default IMAGE_COMPRESSION_QUALITY of 85 as per @tomdyson's suggestion, and simplify image backend now that it doesn't have to check for the presence of a quality setting

wagtail/wagtailimages/backends/base.py

@@ -1,4 +1,3 @@
-from django.db import models
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 
@@ -7,13 +6,8 @@ class InvalidImageBackendError(ImproperlyConfigured):
 
 
 class BaseImageBackend(object):
-    quality = None
-    
     def __init__(self, params):
-        try:
-            self.quality = settings.IMAGE_COMPRESSION_QUALITY
-        except:
-            pass
+        self.quality = getattr(settings, 'IMAGE_COMPRESSION_QUALITY', 85)
         
     def open_image(self, input_file):
         """

wagtail/wagtailimages/backends/pillow.py

@@ -8,20 +8,15 @@ class PillowBackend(BaseImageBackend):
     def open_image(self, input_file):
         image = PIL.Image.open(input_file)
         return image
-        
+
     def save_image(self, image, output, format):
-        if self.quality:
-            image.save(output, format, quality=self.quality)
-        else:
-            image.save(output, format)
-    
-        
+        image.save(output, format, quality=self.quality)
+
     def resize(self, image, size):
         if image.mode in ['1', 'P']:
             image = image.convert('RGB')
         return image.resize(size, PIL.Image.ANTIALIAS)
 
-
     def crop_to_centre(self, image, size):
         (original_width, original_height) = image.size
         (target_width, target_height) = size

wagtail/wagtailimages/backends/wand.py

@@ -7,21 +7,19 @@ from wand.image import Image
 class WandBackend(BaseImageBackend):
     def __init__(self, params):
         super(WandBackend, self).__init__(params)
-        
+
     def open_image(self, input_file):
         image = Image(file=input_file)
         return image
-        
+
     def save_image(self, image, output, format):
         image.format = format
-        if self.quality:
-            image.compression_quality = self.quality
+        image.compression_quality = self.quality
         image.save(file=output)
-        
+
     def resize(self, image, size):
         image.resize(size[0], size[1])
         return image
-        
 
     def crop_to_centre(self, image, size):
         (original_width, original_height) = image.size