Hi Alison - 

I have noticed this myself in a few instances. For example, on a different site/theme/page I found that the attachments were sorted alphabetically by the attachment file type, meaning that PDF files, which had the attachment type name "application" came before images, which had the type name "image/jpeg" -- definitely confusing.

In any case, there is a really good way to code the page template that makes it super easy for someone to determine which attachment gets used without them having to edit the code each time.

Your code probably looks somewhat like this by default:

<img src="{{ post.attachments.first.url }}">

But you could use a liquid forloop to scan through all of the attachments and just take the one with a particular term in the file name, like so:

{% for attachments in post.attachments %}

{% if attachment.file_name contains "thumbnail" %}

<img src="{{ attachment.url }}">

{% endif %}

{% endfor %}

When this is implemented, it will use whatever image has "thumbnail" in the file name. Please note that you should then make sure to only have one attachment with "thumbnail" in the file name for each post.