This question has been answered by Bruno17. See the first response.
--select a user==|| [[getImageList? &docid=`yourDocID` &tvname=`yourMIGXtv` &tpl=`@CODE:[[+username]]==[[+MIGX_id]]` &outputSeparator=`||` ]]
[[getImageList?
&docid=`yourDocID`
&tvname=`yourMIGXtv`
&tpl=`migxUserTpl`
&where=`{"MIGX_id":"[[*migx_user]]"}`
]]