Introducing History palette options and tools in Photoshop

-->Snapshot thumbnail: This is a miniature image of the most recently saved snapshot image, which is a copy of your document with all the current states included.

-->Source state column: Click in this column next to a particular snapshot or state, and when you begin painting with the History Brush tool or when erasing with the Erase to History option, Photoshop uses the snapshot or state you select as the source.

-->History state: This is a particular step or edit in your document’s list of steps. An icon appears in this column showing what kind of action occurred in that state.

-->Active state marker: This slider points to the currently active state. You can drag it up or down to change the current state.

-->Create new document from current state: Click this icon to create a duplicate copy of your image at the currently selected state. Your new document starts out with a clean slate and an empty history list.

-->Create new snapshot: Click this icon to store an image of your document, preserving all the states listed.

-->Delete current state: Click this icon to remove a selected state.

-->Undone states: These are the grayed-out states that are undone when you select an earlier state in the list.

-->Open state: This is the original document when first opened.

-->Current history state: This is the active state you’ve selected in the history list.