I had this problem when I installed my Canon scanner, everything changed.
This worked for me:
Start from the desk top
Go to My Pictures' or wherever you store your pictures on you computer.
Open a folder, then right click on a thumbnail.
Select Properties
Select Opens With, and choose the program you want from the list.You can select to make all photos of this type work in the same way.
I wanted to select Photoshop, but I think it should work with Pixvue.
As for CS2, it can do far more than essentials. Its like getting used to a car with the indicator on the other side. I just changed cars and now my indicator is on the wrong side, anybody got a fix for that!?