If you want to use a different program to open pictures, for example, select that program from the list and then choose Set this program as default. All other formats are set to open with Windows Photo Viewer.
In the example above, Internet Explorer is set to open GIF images and Microsoft Office 2010 is set to open JPG files. You can then click on Set this program as default to have it open all the default file types or you can click Choose defaults for this program to choose specific file types. Select the program and Windows will tell you how many defaults this programs is set to open. If you click on the first link, you’ll get a list of the different programs installed on your computer.
Here you will see the two options I mentioned above: Set your default programs and Associate a file type or protocol with a program.
