If you have cleared the Always ask before opening this type of file check box, you are always prompted when you use a link to a Tagged Image File Format image?

Use Regedit to view HKEY_CLASSES_ROOT\.tif\(default) and HKEY_CLASSES_ROOT\.tiff\(default). If either value is TIFImage.Document, set them both to Imaging.Document.

You could Merge the following .reg file:

REGEDIT4                              \[HKEY_CLASSES_ROOT\.tif\]                              @="Imaging.Document"                              \[HKEY_CLASSES_ROOT\.tiff\]                              @="Imaging.Document"