URL = "https://httpbin.org";
    URL = URL + "/post";

    Image = "https://api.athenaeum.digital/test_data/picture.jpg"; // URL, Path or Binary Data

    Token       = "***";
    Secret      = "***";
    UsersKey    = "***";
    UsersSecret = "***";
    Version     = "1.0";

    NewRequest = OPI_HTTPRequests.NewRequest().Initialize(URL);

    Result = NewRequest
        .StartMultipartBody()
        .AddMultipartFormDataFile("file1", "pic.png", Image, "image/png")
        .AddMultipartFormDataField("field1", "Text")
        .AddMultipartFormDataField("field2", "10")
        .UseMultipartFieldsAtOAuth(False) // <---
        .AddOauthV1Authorization(Token, Secret, UsersKey, UsersSecret, Version)
        .ProcessRequest("POST")
        .ReturnResponseAsJSONObject();