picture manager and my pictures folder not showing same pictures

My mother got a new computer with Office 2007. She deleted some pictures
from her My Pictures folder and they still remained in Picture Manager. Then
we noticed some pictures in her My Pictres folder do not show up in Picture
Manger. What gives? And which area is it that is used for a screensaver?
That is how she knew something was off when pictures she deleted from My
Pictures were still being shown in her screensaver (which is set to show
slideshow from My Pictures) and we discovered the pictures were not in her My
Pictures folder, but showed up in Picture Manager when we opened that up.
Why aren't they connected? Thank you.