Prefixed:

As an arg:

As an modifier:

• #{{i}}:

The above was generated with the following code:

<div id="app">
  <div v-dummy></div>
  <div v-dummy="3">Prefixed: </div>
  <div v-dummy="'3,4'"></div>
  <div v-dummy:3,4>As an arg: </div>
  <div v-dummy.3,4>As an modifier: </div>
  <img v-dummy="'100x100'">
  <img v-dummy:100x100>
  <img v-dummy.100x100>
  <img v-dummy width="150" height="150">
  <img v-dummy="'50x100'">
  <table v-dummy></table>
  <ul v-dummy></ul>
  <ol v-dummy></ol>
  <ul>
    <li v-for="i in 6" v-dummy>#{{i}}: </li>
  </ul>
  <div style="max-width: 500px"><img v-dummy></div>
  <div v-dummy="250"></div>
  <img v-dummy="'100,400x200,400'">
  <img v-dummy:100,400x200,400>
  <div><dummy></dummy></div>
  <div><dummy t="2"></dummy></div>
  <div><dummy txt="1,3"></dummy></div>
  <dummy img="100"></dummy>
  <dummy i="150x100"></dummy>
</div>

<script src="https://unpkg.com/vue"></script>
<script src="https://unpkg.com/vue-dummy"></script>
<script>
  new Vue({el: '#app'});
</script>