Fix disk image cache read not setting memory cache + ensure decodedImageWithImage never fail

@@ -191,16 +191,10 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
 
         dispatch_data_apply(dispatchedData, (dispatch_data_applier_t)^(dispatch_data_t region, size_t offset, const void *buffer, size_t size)
         {
-            UIImage *diskImage = SDScaledImageForPath(key, [NSData dataWithBytes:buffer length:size]);
+            UIImage *diskImage = [UIImage decodedImageWithImage:SDScaledImageForPath(key, [NSData dataWithBytes:buffer length:size])];
 
-            if (image)
+            if (diskImage)
             {
-                UIImage *decodedImage = [UIImage decodedImageWithImage:diskImage];
-                if (decodedImage)
-                {
-                    diskImage = decodedImage;
-                }
-
                 [self.memCache setObject:diskImage forKey:key cost:image.size.height * image.size.width * image.scale];
             }
 

@@ -35,7 +35,7 @@
                                                  colorSpace,
                                                  bitmapInfo);
     CGColorSpaceRelease(colorSpace);
-    if (!context) return nil;
+    if (!context) return image;
 
     CGRect rect = (CGRect){CGPointZero,{CGImageGetWidth(imageRef), CGImageGetHeight(imageRef)}};
     CGContextDrawImage(context, rect, imageRef);