George, It sounds (to me) like this is a consequence of settings in Screen Effects.
1. Open System Preferences/Screen Effects
2. In the Screen Effects tab, ensure "Pictures Folder" is not highlighted/enabled, e.g., choose one of the other options.
3. Adjust the timing in the Activation tab as necessary.
4. Enjoy!
5. If this does not fix things, BIOB!
Harv