1.base64String>>>>byte[]
byte[] img;
string str = Convert.ToBase64String(img);
2.byte[]>>>>>>base64String
string str;
byte[] img = Convert.FromBase64String(str);
1.base64String>>>>byte[]
byte[] img;
string str = Convert.ToBase64String(img);
2.byte[]>>>>>>base64String
string str;
byte[] img = Convert.FromBase64String(str);