The output of the getImageList snippet can be sorted on any of the MIGX form fields. Here's how, from a Slack conversation.
sottwell asked...
MIGX and getImageList. How to sort the output by a given field? I tried "&sort=`area`".
The Solution:
jako says...
It has to be a json string:
&sort=`[{"sortby":"area","sortdir":"ASC"}]`
What's the Story?
The getImageList "sort" property takes a JSON string to specify the MIGX form field to sort by and the sort direction, ASC or DESC.