Once partitioned, one would save them as separate image files, typically in GIF, JPEG or PNG format in either a batch process or one at a time.
On the web, slicing breaks up one large image into many smaller ones, which reduces "page weight" or load time considerably.
Advanced methods of slicing can be used to further compress the amount of data needed to download to the user's computer in order for the web page to display correctly.
These are outlined below: Recent versions of these programs have improved ability to convert artwork directly into CSS, albeit an unorthodox method since the algorithms rely heavily on absolute positioning (for example), which can render (display) inconsistently across modern web browsers.
Multi-layered interfaces may use slices, but may also use vector graphics (including 3D models) with the drawback of added (most often unnoticeable) rendering time and with the advantage of more options and flexibility in altering the appearance of the individual image.