Hi,
What's the error that you're getting when you open those pictures? Do try checking if it's associated properly to open with no error.
- Click Start then select Default Programs.
- Click on "Associate a file type or protocol with a program".
- Look for .jpg, .jpe and .jpeg, click on it then click Change program.
- On the next window that will open select Windows Photo Viewer then click OK.
- Close everything then try opening those picture that will not open again.