Image Transform not working

Question

I have set transforms in admin but when I call those transforms in Twig nothing happens. 'getUrl('thumb')' shows blank in return although when calling like

 <img src="{{ asset.getUrl('thumb') }}"
  width="{{ asset.getWidth('thumb') }}"
  height="{{ asset.getHeight('thumb') }}">

width and height have values but url is blank. Anyone have idea?

Answer 1

I think you are missing the targeting of the asset itself.

If you are calling an Entry's asset from a field that expects one single image you can write:

{% set img = entry.fieldName.one() %}
<img 
   src="{{ img.getUrl('thumb') }}" 
   width="{{ img.getWidth('thumb') }}" 
   height="{{ img.getHeight('thumb') }}" />

If you are doing this in a for loop, or your field allows more than one image to be selected you can write:

{% for item in entry.fieldName %}
    {% set img = item.one() %}
    <img 
       src="{{ img.getUrl('thumb') }}" 
       width="{{ img.getWidth('thumb') }}" 
       height="{{ img.getHeight('thumb') }}" />
{% endfor %}

Answer 2

I think @kelly is correct, and you probably don't have an image to transform. I'd add to @kelly's suggestion a conditional to check, e.g:

{% set img = entry.fieldName.one() %}
{% if img %}
    <img 
        src="{{ img.getUrl('thumb') }}" 
        width="{{ img.getWidth('thumb') }}" 
        height="{{ img.getHeight('thumb') }}" />
{% else %}
    ! Oops! There is no image to transform!
{% endif%}