I’ve been wondering about the settings used for “Save As (.png)” option available in Photoshop. Does it save the highest quality, largest size as a default setting and how does it differ from PNG-24 and PNG-8 in “Save for Web”? Let me know if I can be more detailed in my question.
Save for Web removes all proprietary data from the file resulting in smaller file sizes. Simply saving as PNG will include hidden proprietary data, like meta data for the creation app, app version, time created, etc.
Save for web should always result in smaller file sizes.