The viewer has ten different window layouts you can switch between by holding down the left Alt key and pressing 0-9. When you change window sizes or position the changes will be saved in the current layout and used the next time you run the program.
Layouts 1 to 4 are each assigned to a specific window: Image window(1), Browser window(2), Playlist window(3) and Explorer window(4). These layouts can also be selected by double-clicking the titlebar of the respective window.
When one of the window layouts is selected the Inzomia viewer will try to automatically select the right layout based on your actions. For example if the browser layout is selected and you doubleclick an image in the playlist window the layout will be change to the image layout.