Hi Laurel
For PSP8, You can go to File -> Preferences -> File Locations...
A window will pop up. Select "Picture Tubes" on the left side.
On the right side you can see the folders that PSP8 searches for picture tubes.
For each folder there are three check boxes:
1) The first one marks the folder where your tubes will go after you save them. You can only have one selected at a time.
2) The second check box makes PSP8 search for tubes in its subfolders. So if you want to make subfolders in a particular folder (like Cats and Dogs), be sure that folder option is checked. You don't have to Add new folders.
3) The third check box makes PSP8 search for that folder mentioned.
You can also add and delete folders to search with the buttons in that same window.
Hope this helps!