{% load thumbnail_libs %}

{% sorl_thumbnail self.image.file.name "500x500" upscale=False as im %}
  <img src="{% media im.name %}">
{% endthumbnail %}

{% load thumbnail_libs %}

{% sorl_thumbnail self.image.file.name "500x500" upscale=False as im %}
  <img src="{% media im.name %}" alt="{{ self.image.label }}">
{% endthumbnail %}

Add alt text for image widget
Add alt text for image widget
