//UIImage图片转成Base64字符串：

UIImage *originImage = [UIImage imageNamed:@"originImage.png"];

NSData *data = UIImageJPEGRepresentation(originImage, 1.0f);

NSString *encodedImageStr = [data base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

     

//Base64字符串转UIImage图片：

NSData *decodedImageData = [[NSData alloc] 

initWithBase64EncodedString:encodedImageStr options:NSDataBase64DecodingIgnoreUnknownCharacters];

UIImage *decodedImage = [UIImage imageWithData:decodedImageData];