Saving files is critical part of working with computers, no matter what software you're using. Most software packages offer at least two commands that you can use to save your files — Save and Save As — and inexperienced users are often unsure of which of these two commands to choose. Before we jump in, though, let's take a look at the configurable options in the File Handling section of Photoshop's preferences.
Photoshop offers several settings that you can use to specify the way files are saved. These settings, which vary slightly depending on your operating system, include options for saving file previews, file extensions, and ensuring file compatibility across operating systems. To access them, open Photoshop's Preferences dialog box by pressing Ctrl+K/.cmd;+K, then select File Handling from the list of choices on the left.
The File Handling section of the Preferences dialog box is divided into three main areas — File Saving Options, File Compatibility and Version Cue. The following options are available:
Image Previews. The default Image Preview setting of Always Save embeds a tiny preview of your image into each document you save. This preview is displayed by your operating system and allows you to see what the image looks like before you open it. On the Mac you have several additional options for saving thumbnails: ...