How to replace Explorer's TIF image handler?

I've created a thumbnail image handler (shell extension) for Windows Explorer, for handling several TIF/TIFF image formats. I know that Explorer already includes TIFF support (provided by the shimgvw.dll extension, which comes with Windows XP), but I want to replace it with my own image handler extension.

If I register my extension (via ShellEx/{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}), and unregister shimgvw.dll (via regsvr32 /u shimgvw.dll), my thumbnail handler extension works, but this creates a problem: shimgvw.dll also handles thumbnails for several common image formats lik开发者_运维百科e BMP, JPG, PNG, etc, so after unregistering it, support for these formats gets disabled.

Is there any way to make my extension work (just for .tif files) without having to unregister shimgvw.dll? Thanks in advance!

I dont understand your question. Reproduce your tasks:

1. Create thumbnail handler

2. Register this under tiff\shellex{bb2e617c... alias image extractors

3. Unregister shimgvw - why?

If you register your dll to handle tiff thumbnails, is useless unregister shimgvw.