复制下面的内容到一个空白的记事本文件中，然后保存为.reg，至于文件名称就随便取吧，不影响结果，然后双击生成的文件，系统提示导入注册表，直接确定就可以了。
Windows Registry Editor Version 5.00
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.jpg]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.jpeg]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.gif]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.png]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.bmp]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.tiff]@="PhotoViewer.FileAssoc.Tiff"
; Change Extension's File Type[HKEY_CURRENT_USER\Software\Classes\.ico]
@="PhotoViewer.FileAssoc.Tiff"
