将灰度图像读取到数组中，然后再绘制的屏幕上

char p1[2500];  //50*50

BOOL ReadGrayImg(CString path, char* pFlashImg)
{

memset(pFlashImg,0,sizeof(char)*2500);
CImage Img;
Img.Load(path);

int nWidth = Img.GetWidth();
int nHeight = Img.GetHeight();

for(int i = 0; i < nHeight; i++)
{
for(int j = 0; j < nWidth; j++)
{
pFlashImg[i*nWidth+j]=Img.GetPixel(i,j);
}

}

return TRUE;
}

void CGdiTestDlg::MyDraw(){

int nWidth =  50;
int nHeight = 50;

int nValue=0;

CDC* pDC=GetDC();

for(int i = 0; i < nHeight; i++)
{
for(int j = 0; j < nWidth; j++)
{
nValue=p1[i*nWidth+j];
pDC->SetPixel(i,j,RGB(nValue,nValue,nValue));

}
}
ReleaseDC(pDC);

}