How can I get default file associations for specific file extension '.jpg'?

Question

I want to find some file association that "open with.." can find at XP/Win7/Win8, I try to find "PhotoShop".

1. First, I find the HKEY_CLASSES_ROOT.jpg

   PerceivedType = image
   \OpenWithProgids => jpegfile and Paint.NET.1
   

2. So, I find HKEY_CLASSES_ROOT\SystemFileAssociations\ .jpeg

And it still not found anything about Photoshop.

Is my searching rule right? or Windows use another rule to find PhotoShop command line?

Now, if I right click .jpg file and click "open with..". It would show many programs can let us select, just like PhotoShop, Paint, Paint.NET, Windows Media Center, Windows Photo Viewer, etc.

I need to find the rule that OS can find file association with .jpg. Actually, I want to define this rule that can find all these application and work fine at Windows XP/7/8.

Answer 1

I would suggest making this change without using the registry!

An easy way to change association to another program is to right click on the file type, and select Open With -> Choose default program. Then select the program you want and ensure the box "always use the selected program to open this kind of file".

Or, click start menu, and select Default Programs (also accessible from inside Control Panel).

You have the option here under Associate a file type or protocol with a program (where you can navigate to .jpeg)

Answer 2

There should be another key

HKEY_CLASSES_ROOT\jpegfile

Have a look there.