- (NSString *)base64String:(UIImage *)image {
    NSData * data = [UIImagePNGRepresentation(image) base64EncodedDataWithOptions:NSDataBase64Encoding64CharacterLineLength];
    return [NSString stringWithUTF8String:[data bytes]];
}

NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:shareEntity.photoContentStr options:1];
UIImage *image = [UIImage imageWithData:decodedData];