The white area in 101 is a group. A group can hold up to 150 screen shots. If you fill your first group, there are 20 others. You select the group you want from the Group menu.
When you first install 101 your groups are pre-named group Group 1 to group Group 20. To rename a group, click "Rename Group" on the Group menu.
The name of the currently selected group is shown in the 101 title bar.