下载图片

// 1.下载图片
NSURL *url = [NSURL URLWithString:@"https://www.baidu.com/img/bd_logo1.png"];
// url中文编码，防止乱码
url = [url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSData *data = [NSData dataWithContentsOfURL:url];
// 2.将二进制转换为图片
UIImage *image = [UIImage imageWithData:data];