МП
public static void Merge(ref string pck)
{
if (new FileInfo(pck).Length < 2147483393)
{
string pkx = pck.Replace(".pck", ".pkx");
if (File.Exists(pkx))
{
Console.WriteLine("\nСоединяем pck и pkx в новый файл");
if (File.Exists(pck + "x")) File.Delete(pck + "x");
File.Copy(pck, pck + "x");
CopyStream(new FileStream(pkx, FileMode.Open, FileAccess.Read), new FileStream(pck + "x", FileMode.Open, FileAccess.Write), 134217728);
pck = pck + "x";
}
}
}