Helping people with computers... one answer at a time.
Many people prefer alternatives to Windows Picture and Fax Viewer. Others prefer it. Here's how to reset it to be the default image viewer.
A very common question most folks have shortly after installing Windows XP is How do I make something other than "Picture and FAX Viewer" the default for viewing pictures?.
The other day I got a couple of variations on the reverse:
What is the file name and extension for Windows picture and fax viewer? I want to use it for an OLE object to view pictures.
How do I change my default image viewer back to the Windows Picture and Fax Viewer?
Turns out it's easier to get rid of than it is to restore. But not impossible.
It took a little spelunking using Process Explorer to determine the command line that is used when Windows Picture and Fax Viewer is invoked. Turns out that it's not a stand-alone exe at all.
The command to run Windows Picture and Fax viewer is:
rundll32.exe C:\WINDOWS\System32\shimgvw.dll,ImageView_Fullscreen path-to-picture
So, to answer the first question: shimgvw.dll probably exposes the objects needed to use Windows Picture and Fax Viewer as an OLE object.
As for the second, restoring Windows Picture and Fax Viewer as the viewer for images:
If for some reason it's not already in the list, you can force the association by following these steps, still in Windows Explorer:
C:\WINDOWS\system32\rundll32.exe C:\WINDOWS\System32\shimgvw.dll,ImageView_Fullscreen %1. Where "C:\WINDOWS" is the directory containing your Windows installation.
You'll want to repeat that for every extension (GIF, JPG, JPEG, etc.) for which you want to change the behavior.
Update: Another approach to re-installing Windows Picture and Fax Viewer is to click on Start, Run... and type in:
regsvr32 /i shimgvw.dll
and press OK. Then press OK again on the resulting success message. (Thanks to comment poster Leon for this suggestion.)