static int getPixelFormat(int pixelSize, int flags)
{
	if(pixelSize==1) return TJPF_GRAY;
	if(pixelSize==3)
	{
		if(flags&TJ_BGR) return TJPF_BGR;
		else return TJPF_RGB;
	}
	if(pixelSize==4)
	{
		if(flags&TJ_ALPHAFIRST)
		{
			if(flags&TJ_BGR) return TJPF_XBGR;
			else return TJPF_XRGB;
		}
		else
		{
			if(flags&TJ_BGR) return TJPF_BGRX;
			else return TJPF_RGBX;
		}
	}
	return -1;
}