public class Row : ArcGIS.Core.CoreObjectsBase, System.IDisposable  

public async Task ReadBlobField(Table table, QueryFilter queryFilter, string blobFieldName)
{
  await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
  {
    const string imageFileBaseName = "C:\\path\\to\\image\\directory\\Image";

    // for each row that satisfies the search criteria, write the blob field out to an image file
    using (RowCursor rowCursor = table.Search(queryFilter))
    {
      int fileCount = 0;
      while (rowCursor.MoveNext())
      {
        using (Row row = rowCursor.Current)
        {
          // Read the blob field into a MemoryStream
          MemoryStream memoryStream = row[blobFieldName] as MemoryStream;

          // Create a file
          using (FileStream outputFile = new FileStream(imageFileBaseName + fileCount.ToString(), FileMode.Create, FileAccess.Write))
          {
            // Write the MemoryStream into the file
            memoryStream.WriteTo(outputFile);
          }
        }
      }
    }
  });
}