Images displayed broken

Hey!

The Images im my Decker slides aren't displayed. Insted the name and the "broken image" image appears.

Example

I tried to run it on other browsers (Firefox, Chome, Edge) but the same problem occurred. In the shell no error occourred but in the web console is this ReferenceError.

ReferenceError: $ is not defineddecker.js:93:3
    addSourceCodeLabels  http://localhost:8888/support/js/decker.js:93
    deckerStart          http://localhost:8888/support/js/decker.js:18
    dispatchEvent        http://localhost:8888/support/vendor/reveal/js/reveal.js:1995
    start                http://localhost:8888/support/vendor/reveal/js/reveal.js:686

The Problem even occours if I simply run the unmodified tutorial. I am running decker on a Windows 10 OS.

Thanks for your support!