1、直接获取

NSData*data = [NSDatadataWithContentsOfURL:[NSURLURLWithString:@"http://s12.mogujie.cn/b7/bao/131011/1jix9_kqywmrcdkfbg26dwgfjeg5sckzsew_400x540.jpg_200x999.jpg"]];

UIImage*image = [UIImageimageWithData:data];

NSLog(@"w = %f,h = %f",image.size.width,image.size.height);

2、//需要用到第三方库SDWebImage

UIImageView*v1 = [[UIImageViewalloc]init];

[self.viewaddSubview:v1];

[v1sd_setImageWithURL:[NSURLURLWithString:imageNameplaceholderImage:[UIImageimageNamed:@"default1"]options:SDWebImageRetryFailedcompleted:^(UIImage*image,NSError*error,SDImageCacheTypecacheType,NSURL*imageUrl){

CGSizesize = image.size;

CGFloatw = size.width;

CGFloatH = size.height;

}];