You’re going to have to set the images on each post.
I see you have that already.
---
photo: 2_qoute.png
---
Then what you need to do in your photoblog.html layout is use the HTML img tag.
{%- for post in site.posts -%}
<div>
<h2>{{ post.title }}</h2>
{% assign photo_path = '/img/large/' | append: post.photo %}
<img src="{{ photo_path | relative_url }}" />
</div>
{% endfor %}