使用c++，生成后的文件有数据，可是在windows中打开显示的是乱七八糟的一些颜色，这只是针对jpeg的，如果生成png，在windows中打开都不行。
有在c++中使用过gd的吗？谢谢帮忙看看。

代码是官方的示例：

int main() 

{ 

	/* Declare the image */  

	gdImagePtr im;  

	/* Declare output files */  

	FILE *pngout, *jpegout; 

	/* Declare color indexes */

	int black;  int white;

	/* Allocate the image: 64 pixels across by 64 pixels tall */



	im = gdImageCreate(64, 64);

	/* Allocate the color black (red, green and blue all minimum).    Since this is the first color in a new image, it will    be the background color. */

	black = gdImageColorAllocate(im, 0, 0, 0);

	/* Allocate the color white (red, green and blue all maximum). */

	white = gdImageColorAllocate(im, 255, 255, 255);

	/* Draw a line from the upper left to the lower right,    using white color index. */

	gdImageLine(im, 0, 0, 63, 63, white);

	/* Open a file for writing. "wb" means "write binary", important    under MSDOS, harmless under Unix. */

	pngout = fopen("test.png", "wb");

	/* Do the same for a JPEG-format file. */

	jpegout = fopen("test.jpg", "wb");

	/* Output the image to the disk file in PNG format. */

	gdImagePng(im, pngout);

	/* Output the same image in JPEG format, using the default    JPEG quality setting. */

	gdImageJpeg(im, jpegout, -1);   /* Close the files. */

	fclose(pngout);

	fclose(jpegout);  

	/* Destroy the image in memory. */

	gdImageDestroy(im);

}