To view any of your created images it is best to use the file browser in the toolbar menu, different buttons on the options bar will give you a number of ways to view your images one of which will allow you to quickly open up the browser and view high quality images alongside custom-sized thumbnails.
If you are making numerous adjustments to you’re images involving using a lot of layers your best option is to use layer comps, these will let you capture configurations of a document by recording the position, visibility and blending options of the layers which means you can later find a layer comp from the palette and reuse the setting and way everything was set at that stage.
Layers are the building blocks of many image creation workflows, especially if you are building up a document or a image from a number of other images. You may not need to work with layers if you are doing simple image adjustments, but layers help you work efficiently and are essential to most nondestructive image editing.