Removing unecessary class from image component that was adding a white background and border to images (#161)

Author: alexcolbeck1

docs/_includes/components/image.html

@@ -1,13 +1,6 @@
-<figure class="nhsuk-image {{ include.classes | xml_escape }}">
-  {% assign src = '/assets/images/' | prepend: site.baseurl | append: include.src %}
-  {% if include.src contains 'https://' %}
-  <img class="nhsuk-image__img" src='{{ include.src | uri_escape }}' alt='{{ include.alt | xml_escape }}' />
-  {% else %}
-  <img class="nhsuk-image__img" src='{{ src }}' alt='{{ include.alt | xml_escape }}' />
-  {% endif %}
-  {% if include.caption %}
-  <figcaption class="nhsuk-image__caption">
-    {{ include.caption }}
-  </figcaption>
-  {% endif %}
-</figure>
+{% assign src = '/assets/images/' | prepend: site.baseurl | append: include.src %}
+{% if include.src contains 'https://' %}
+<img class="nhsuk-image__img" src='{{ include.src | uri_escape }}' alt='{{ include.alt | xml_escape }}' />
+{% else %}
+<img class="nhsuk-image__img" src='{{ src }}' alt='{{ include.alt | xml_escape }}' />
+{% endif %}