新建一个后缀名为.reg的文件，然后将下面代码复制粘贴到文本中，保存运行即可
Windows Registry Editor Version 5.00 ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.jpg] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.jpeg] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.gif] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.png] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.bmp] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.tiff] @="PhotoViewer.FileAssoc.Tiff" ; Change Extension's File Type [HKEY_CURRENT_USERSoftwareClasses.ico] @="PhotoViewer.FileAssoc.Tiff"