Not really sure what image you are talking about, since you didn't provide an example.
The list of built-in icons is (as far as I know) limited to those listed on the page below:
http://jquerymobile.com/test/docs/buttons/buttons-icons.htmlThe built-in icons are all contained in a single file, which is in the distribution in four variations: icons-18-black.png, icons-19-white.png, icons-36-black.png, icons-36-white.png.
chevronCircle.png is not "included in the distribution". If you have some icon you'd like to use, you can also use your own custom icon:
Custom Icons
To use custom icons, specify a data-icon value that has a unique name like myapp-email and the button plugin will generate a class by prefixing ui-icon- to the data-icon value and apply it to the button. You can then write a CSS rule that targets the ui-icon-myapp-email
class to specify the icon background source. To maintain visual
consistency, create a white icon 18x18 pixels saved as a PNG-8 with
alpha transparency.
