How to Save a PSD File for Older Versions of Photoshop
This setting is persistent, so you’ll only need to set it once. Ensure that the area at the bottom of the File Compatibility area is set toAlwaysorAsk. Turning this option on, however, results in larger file sizes. If you only need this feature occasionally, set it toAsk. This way, Photoshop will ask you if you want to maximize compatibility every time you save a file. When this compatibility option is invoked, the layers are saved along with a flattened composite of the image....