: Go to Edit > Preferences > File Handling > Maximize PSD File Compatibility. Make sure this is set to "Always" or "Ask." Turning this option on, results in larger file sizes. If you only need this feature occasionally, you can set it to "Ask" and Photoshop will ask you if you want to maximize compatibility every time you save a file. When this option is used, the layers are saved along with a flattened composite of the image.