in photoshop, we can "link" the layers to select and edit linked layers at the same time while maintaining the order of the layers.
(https://helpx.adobe.com/photoshop/using/selecting-grouping-linking-layers.html)
When creating images such as attachments, I can't group them(paperclip) because I'm afraid the order will change. link feature such as photoshop(link layers) will be very useful in this situation..