Uploading Image/File via CSOM from ASP web app to SharePoint Online - asp.net

Question

Novice developer here with an issue I would appreciate some assistance with :-)
I am developing an ASP web application (a simple bulletin board, which allows users to create buy and sale adverts). All of my data is being stored/retrieved from an MSSQL database. However, I wish to store/retrieve images for the adverts using a SharePoint Online library.
I am struggling at the first hurdle, which is uploading the image to the library. I've debugged and debugged some more but I am still hitting a brick wall. After many hours of trying, I now have the code below, which is no longer returning any errors although the image never appears in the destination library.
Given all the above, I would sincerely appreciate any assistance from any experts out there!
The following code fires when the "create advert" button is pressed.
string currentUserName =
System.DirectoryServices.AccountManagement.UserPrincipal.Current.DisplayName;
SqlConnection conn2;
SqlCommand comm2;
SqlDataReader reader;
string connectionString2 =
ConfigurationManager.ConnectionStrings["CCString"].ConnectionString;
conn2 = new SqlConnection(connectionString2);
comm2 = new SqlCommand("SELECT TOP 1 * FROM Threads WHERE ([AdvertiserName] = '" + currentUserName + "') ORDER BY PostCreationDateTime DESC", conn2);
conn2.Open();
reader = comm2.ExecuteReader();
reader.Read();
Guid imageID;
string imageIDConfirmed = "";
string fileExtension = "";
if (reader["UniqueImageID"].GetType().Name != "DBNull")
{
imageID = (Guid)reader["UniqueImageID"];
imageIDConfirmed = imageID.ToString().Replace(":", "-");
string myFile = jpgFileUpload.FileName;
fileExtension = myFile.Substring(myFile.Length - 4, 4);
}
reader.Close();
conn2.Close();
string username = "username#emailaddress.com";
string password = "password";
System.Security.SecureString securePass = new
System.Security.SecureString();
foreach (char ch in password.ToCharArray()) securePass.AppendChar(ch);
SharePointOnlineCredentials credentials = new
SharePointOnlineCredentials(username, securePass);
using (ClientContext client = new
ClientContext("https://company.sharepoint.com/sites/SiteName/"))
{
var formLib = client.Web.Lists.GetByTitle("Documents");
client.Credentials = credentials;
client.Load(formLib.RootFolder);
client.ExecuteQuery();
string fileName = #"C:\Temp\" + jpgFileUpload.FileName;
jpgFileUpload.SaveAs(fileName);
var fileUrl = "";
int fileLen;
fileLen = jpgFileUpload.PostedFile.ContentLength;
byte[] input = new byte[fileLen - 1];
input = jpgFileUpload.FileBytes;
UploadDocument(#"https://company.sharepoint.com/sites/SiteName/", "Documents", "https://company.sharepoint.com/sites/SiteName/Shared%20Documents/", "testDocument", input);
using (var fs = new FileStream(fileName, FileMode.Open))
{
var fi = new FileInfo(imageIDConfirmed + fileExtension);
fileUrl = String.Format("{0}/{1}", formLib.RootFolder.ServerRelativeUrl, fi.Name);
Microsoft.SharePoint.Client.File.SaveBinaryDirect(client, fileUrl, fs, true);
client.ExecuteQuery();
}
var libFields = formLib.Fields;
client.Load(libFields);
client.ExecuteQuery();
Microsoft.SharePoint.Client.File newFile =
client.Web.GetFileByServerRelativeUrl(fileUrl);
Microsoft.SharePoint.Client.ListItem item = newFile.ListItemAllFields;
item["Title"] = "Any Title";
item["File Name"] = "Any File Name";
item.Update();
client.Credentials = credentials;
client.ExecuteQuery();

Answer 1

which is no longer returning any errors although the image never appears in the destination library
Is it possible that the files are there but are in some unchecked-in state?
As a site collection admin, go to Documents -> Settings -> "Permissions and Management" section -> Manage files which have no checked in version.
If there are files with no checked in version, this could indicate the need to provide check-in logic in your code, or there might be an issue with required fields.