private void ReadHeader()
{
String id = "";
for (int i = 0; i < 6; i++)
{
id += (char) Read();
}
if (!id.StartsWith("GIF"))
{
status = StatusFormatError;
return;
}
ReadLSD();
if (gctFlag && !Error())
{
gct = ReadColorTable(gctSize);
bgColor = gct[bgIndex];
}
}