Try to fix decode image error message

Author: Olivier Poitrey

SDWebImage/SDWebImageDecoder.m

@@ -17,14 +17,13 @@ + (UIImage *)decodedImageWithImage:(UIImage *)image
     CGImageRef imageRef = image.CGImage;
     CGSize imageSize = CGSizeMake(CGImageGetWidth(imageRef), CGImageGetHeight(imageRef));
     CGRect imageRect = (CGRect){.origin = CGPointZero, .size = imageSize};
-	
+
     CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
-    CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
-    CGContextRef context;
-    context = CGBitmapContextCreate(NULL, imageSize.width, imageSize.height, 8, imageSize.width * 4, colorSpace, bitmapInfo);
+    CGContextRef context = CGBitmapContextCreate(NULL, imageSize.width, imageSize.height, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpace, CGImageGetBitmapInfo(imageRef));
     CGColorSpaceRelease(colorSpace);
-    
-    if (!context) return nil;
+
+    // If failed, return undecompressed image
+    if (!context) return image;
 
     CGContextDrawImage(context, imageRect, imageRef);
     CGImageRef decompressedImageRef = CGBitmapContextCreateImage(context);