Edit View: the main area for editing. You may make edit here, creating, shifting and zooming photo freely.
Folder View: To select a folder here, then all photos under this folder shall be listed in Thumbnail View automatically.
Thumbnail View: It lists preview of all photos under the selected folder. You could shift any photo from it to edit page.
Preview View: Click a photo in Thumbnail View, the clicked photo shall be previewed in this area.
Mask View: Here displays preview of all masks contained in system. Select a photo in edit page and then select a mask in Mask View, the mask shall be applied on that photo automatically.