A preview may refer to any of the following:
1. In general, a preview refers to a feature that allows you to glimpse or view something in part or whole without it being opened. For example, a picture preview would show a small version of the picture and give you a good idea what each picture is without opening each picture.
2. Preview is an image and PDF viewer program for the macOS. Preview may be used to view, print, and save pictures. It may also be used to print PDF files.
3. A print preview shows how a page or document looks when printed. See our print preview definition for complete information and related links and terms.
4. A live preview shows an example of how something appears once published. For example, an HTML live preview gives the web developer an idea on how the page looks in a browser. See our live preview page for full information.