Have you ever wished you could easily preview your original image, before you added several layers to it?
It’s good practice, when working in Photoshop, to always keep your “Background” layer as your original unedited image. So, what if you add several layers of editing on top of this image, and you want to go back and easily preview what the image looked like before that? If you’ve added several layers on top of this image, you don’t have to hide each layer individually to see what you started with. Here’s a quick shortcut for toggling all layers to be hidden, except for your background image, allowing you to see your before/after quite easily!
Hold down the OPTION key (on Mac), or ALT key (on PC) while clicking on the little eyeball icon on your background layer, in the layers palette. This will toggle all of the additional layers visibilities, allowing you to see the before/after effects of your processing.