why do you consider saving changes any different in photoshop than it would be in preview? you wouldn't have to export anything, just file>save as. if this truly seems overly tedious, perhaps you really SHOULD be using photoshop, as you can create custom actions to batch edit tons of photos with 1 click, all while saving them to .jpgs, or .tiffs in a neatly organized folder. If you have access to photoshop or pixelmator, i couldn't imagine why you would prefer to use preview. i actually get frustrated when i accidentally double click a file and it opens in preview while I'm browsing through files. I'm sorry this is not really helpful to your original question, but you might not want to get too attached to any particular feature of Apple software moving forward, as they seem to be on a streak of abruptly changing software functionality, usually resulting in the removal of features. you know what feature i miss? scroll bar arrows. you should be happy that at least you have alternatives to the feature you miss.