通常吧JPEG图片导入到VC++中，都是转变了格式->HBITMAP，
我想问他的图片信息怎么获得，就像BMP一样，有个指针，里面就是图片的信息，可以进行处理。
那JPEG图片的这个指针在哪啊
我是想做JPEG图片的数字水印

int GetObject(
  HGDIOBJ hgdiobj,  // handle to graphics object
  int cbBuffer,     // size of buffer for object information
  LPVOID lpvObject  // buffer for object information
);
Parameters
hgdiobj
[in] Handle to the graphics object of interest. This can be a handle to one of the following: a logical bitmap, a brush, a font, a palette, a pen, or a device independent bitmap created by calling the CreateDIBSection function.
cbBuffer
[in] Specifies the number of bytes of information to be written to the buffer.
lpvObject
[out] Pointer to a buffer that receives the information about the specified graphics object.
The following table shows the type of information the buffer receives for each type of graphics object you can specify with hgdiobj. Object type Data written to buffer
HBITMAP BITMAP
HBITMAP returned from a call to CreateDIBSection DIBSECTION, if cbBuffer is set to sizeof(DIBSECTION), or BITMAP, if cbBuffer is set to sizeof(BITMAP)
HPALETTE A WORD count of the number of entries in the logical palette
HPEN returned from a call to ExtCreatePen EXTLOGPEN
HPEN LOGPEN
HBRUSH LOGBRUSH
HFONT LOGFONT



If the lpvObject parameter is NULL, the function return value is the number of bytes required to store the information it writes to the buffer for the specified graphics object.