how to give unique id's to images?

 public enum StringType
        {
            Numeric = 1, Alpha = 2, AlphaNumeric = 3
        }

 public static string GenerateRandomString(StringType stype, int numberOfChars)
        {
            string s = "";
            string alphas = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //if you want to add other charaters add it here - zero and O are removed to avoid confusion
            string alphanumeric = "1234567890ABCDEFGHIJKLMNPQRSTUVWXYZ";
            Random rnd = new Random();

            for (int i = 0; i < numberOfChars; i++)
            {
                if (stype == StringType.Numeric)
                {
                    s = String.Concat(s, rnd.Next(10).ToString());
                }
                else if (stype == StringType.Alpha)
                {
                    s = String.Concat(s, alphas.Substring(rnd.Next(24), 1));
                }
                else
                {
                    s = String.Concat(s, alphanumeric.Substring(rnd.Next(33), 1));
                }

            }
            return s;
        }

Pass no. character for random generated string and enumeration of the stringType define above.

use following function to generate the random strings and add them to your images names while uploading in your file.SaveAs() method.

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