加载gif图片，会导致suggestHeight为NaN.

[yvanda]

加载gif图片crash，会导致suggestHeight为NaN. 跟踪调试了下，是除以0导致的。

• (CGFloat)_resizeImageStorage:(LWImageStorage )imageStorage image:(UIImage )image { CGSize imageSize = image.size;//0, 0 CGFloat imageScale = imageSize.height/imageSize.width; CGSize reSize = CGSizeMake(imageStorage.bounds.size.width,imageStorage.bounds.size.width * imageScale); CGFloat delta = reSize.height - imageStorage.frame.size.height; imageStorage.frame = CGRectMake(imageStorage.frame.origin.x, imageStorage.frame.origin.y, imageStorage.frame.size.width, imageStorage.frame.size.height + delta); return delta; }

下面代码不进去直接跳出： SDImageFormat imageFormat = [NSData sd_imageFormatForImageData:data]; if (imageFormat == SDImageFormatGIF) {

                                                      //GIF
                                                      LWGIFImage* gif = [[LWGIFImage alloc] initWithGIFData:data];
                                                      dispatch_main_async_safe(^{
                                                          if (gif && (options & SDWebImageAvoidAutoSetImage) && completedBlock) {
                                                              completedBlock(gif,data,error);
                                                              return;

                                                          } else if (gif) {
                                                              sself.image = nil;
                                                              sself.gifImage = gif;
                                                              [sself setNeedsLayout];

                                                          } else {

                                                              if ((options & SDWebImageDelayPlaceholder)) {
                                                                  sself.gifImage = nil;
                                                                  sself.image = placeholder;
                                                                  [sself setNeedsLayout];
                                                              }
                                                          }

                                                          if (completedBlock && finished) {
                                                              completedBlock(gif,data,error);
                                                          }
                                                      });

请麻烦尽快修复一下，最近在做这方面的功能，想借鉴大神的demo。