This Tweak will remove the default Windows Image Viewer.

1. Open Start menu and select Run.
    
2. type "cmd".
   
   

   Picture 1

3. Then type "regsvr32 /u shimgvw.dll" (see picture 1) to unregister this dll file. This will stop it from previewing any image's format that it support such as JPEG, Bitmap, GIF.
    
4. Before performing this tweak, make sure you have the alternative Image Viewer e.g. ACDsee, FireGraphic, Ulead Photo Explorer... Because once you do this tweak without that application installed, you can't open and view your image anymore! So, type "regsvr32 shimgvw.dll" in command prompt to undo this tweak.