The Windows Phone SDK comes with a set of icons that you can use freely in your app. The default location of the icon images is C:\Program Files (x86)\Microsoft SDKs\Windows Phone\v8.0\Icons\. Other free icon packs are also available online.
The icon image, for the
ApplicationBarIconButton, should measure 48 by 48 pixels, but with a central area of 26 by 26 pixels. All content should be placed within a 26*26 square pixel area to ensure that it does not overlap the automatic circular button frame. Images that are other sizes will be scaled to fit, but image quality will be lower as a consequence.
The circle displayed on each icon button is automatically generated by the application bar, and therefore should not be included ...