Betfair C# WPF multi tread download and save png files

This is part of a working Betfair project . The png files are the jockeys colours that I am inserting into a datagridview. I don't fully understand multi threading hence my program hangs waiting for these files to download. If you don't have betfair api access you can get the files location by going to [login to view URL] , horse racing and select any race apart from USA meetings. Right click the jockeys colors and select copy image location. The file isn't available after the races are completed. ie; [login to view URL] When the file has downloaded I would like to save it to a folder C:\Colours named as above [login to view URL] . Check to see if file exists first then save. string url = "[login to view URL]"; foreach (var runner in [login to view URL]) { RunnerLineGrid line = new RunnerLineGrid(); [login to view URL]("COLOURS_FILENAME", out string fileurl); if (fileurl != "" ) { url = url + fileurl; Uri fileUri = new Uri(url); Another thread ? -------> BitmapImage bitmapImage = new BitmapImage(fileUril) // if ([login to view URL]) [login to view URL](500); [login to view URL] = bitmapImage; //insert into datagridview } [login to view URL](line); Please only apply if you can or have done this . Any questions please ask.