Multiple image transforms of same image in template
You might consider setting a variable for the image, then one for each transform type.

{% set thumb = { mode: 'crop', width: 300, height: 300 } %}
{% set large = { width: 600 } %}

{% for photo in photos %}
    {% set p = photo.image.first() %}
    &lt;div&gt;
        &lt;a href="{{ p.getUrl(large) }}"&gt;&lt;img src="{{ p.getUrl(thumb) }}"&gt;&lt;/a&gt;
    &lt;/div&gt;
{% endfor %}