You can change the behavior of the history by selecting options in the History Options dialog box. In the History Palette pull-down menu, choose History Options to view or change these settings (see Figure 11.3):
Automatically Create First Snapshot produces a snapshot of the original image upon opening it and places its thumbnail at the top of the History palette (see the next section, Working with Snapshots ).
Automatically Create New Snapshot When Saving generates a snapshot of the current state when saving and adds its thumbnail to the top of the History palette.
Allow Non-Linear History enables you to discard or edit a previous History state without deleting more recent states.
Show New Snapshot Dialog By Default automatically displays the Snapshot dialog box when a new snapshot is created, prompting you to name the snapshots as they are made.