Generator allows you to create image assets in real time as you work, eliminating the tedious steps of copying, slicing and exporting each layer manually, and saving you hours of time. Simply add a file extension to the name of your layer or layer group, and Photoshop will automatically create a JPG, PNG or GIF from the contents of that layer. If you make a change to that layer, the file is immediately updated. This means that you now have a folder of images that are always up-to-date with your Photoshop design.
Photoshop introduced integrated asset slicing for Photoshop CC users today. Will be interesting to see how usefull designers around the web think it is, since I’m not a CC-subscriber (at least yet).