采用GDI+实现BMP到JPG互相转换
使用方式:
1.由于用到了GDI+所以要在工程中设置包括GDI+头文件及库
2.拷贝BmpTransJpg.dll到程序运行目录,工程中包含PictureConvert.h文件,隐式或显示连接BmpTransJpg.lib
3.生成CPictureConvert对象,调用ConvertPictrue方法转换
4.调用直接转换到内存时,转换完成后一定要调用PictureMemFree或PictureRealFree以免内存泄漏.

示例1:
CPictureConvert PictureConvert;//全局对象
BOOL bOK = PictureConvert.ConvertPictrue("test.bmp", "test.jpg", CONVERT_TO_JPG);

示例2:
char *pBuf = NULL;
DWORD bufSize=0;
BOOL bOK = convert.ConvertPictrue("test.bmp", &pBuf, &bufSize, CONVERT_TO_JPG);
//...对pBuf作此处理
convert.PictureMemFree(&pBuf);