VC picture控件显示透明图片，并移动图片，透明可以了，但是有重影？

======================================================================== MICROSOFT FOUNDATION CLASS LIBRARY : movepic ======================================================================== AppWizard has created this movepic application for you. This application not only demonstrates the basics of using the Microsoft Foundation classes but is also a starting point for writing your application. This file contains a summary of what you will find in each of the files that make up your movepic application. movepic.dsp This file (the project file) contains information at the project level and is used to build a single project or subproject. Other users can share the project (.dsp) file, but they should export the makefiles locally. movepic.h This is the main header file for the application. It includes other project specific headers (including Resource.h) and declares the CMovepicApp application class. movepic.cpp This is the main application source file that contains the application class CMovepicApp. movepic.rc This is a listing of all of the Microsoft Windows resources that the program uses. It includes the icons, bitmaps, and cursors that are stored in the RES subdirectory. This file can be directly edited in Microsoft Visual C++. movepic.clw This file contains information used by ClassWizard to edit existing classes or add new classes. ClassWizard also uses this file to store information needed to create and edit message maps and dialog data maps and to create prototype member functions. res\movepic.ico This is an icon file, which is used as the application's icon. This icon is included by the main resource file movepic.rc. res\movepic.rc2 This file contains resources that are not edited by Microsoft Visual C++. You should place all resources not editable by the resource editor in this file. ///////////////////////////////////////////////////////////////////////////// AppWizard creates one dialog class: movepicDlg.h, movepicDlg.cpp - the dialog These files contain your CMovepicDlg class. This class defines the behavior of your application's main dialog. The dialog's template is in movepic.rc, which can be edited in Microsoft Visual C++. ///////////////////////////////////////////////////////////////////////////// Other standard files: StdAfx.h, StdAfx.cpp These files are used to build a precompiled header (PCH) file named movepic.pch and a precompiled types file named StdAfx.obj. Resource.h This is the standard header file, which defines new resource IDs. Microsoft Visual C++ reads and updates this file. ///////////////////////////////////////////////////////////////////////////// Other notes: AppWizard uses "TODO:" to indicate parts of the source code you should add to or customize. If your application uses MFC in a shared DLL, and your application is in a language other than the operating system's current language, you will need to copy the corresponding localized resources MFC42XXX.DLL from the Microsoft Visual C++ CD-ROM onto the system or system32 directory, and rename it to be MFCLOC.DLL. ("XXX" stands for the language abbreviation. For example, MFC42DEU.DLL contains resources translated to German.) If you don't do this, some of the UI elements of your application will remain in the language of the operating system. /////////////////////////////////////////////////////////////////////////////