Certainly, consistency is an important consideration for Source Citations.
I was fascinated that your description focusses on Census records yet your aide-memoir notice does not mention Census.
You say “if you add an image in the Fact/Citation area it doesn’t appear in the Source Pane area”.
Indeed, images added directly to Facts do not appear in any Source area, but do appear elsewhere.
Images added to Citations most definitely do appear alongside images added to Source records.
They can be accessed via the ‘Show Media’ button in both the Facts tab and the yellow Sources For pane.
They appear in the ‘Sources’ section in Reports.