Where does Mac Messages store older Attachments? I'm looking for one specific photograph, a jpg taken on my iPhone, which I know was sent to my partner over Messages, towards the end of 2019. I don't have it in what used to be Camera Roll on the phone nor in Photos.app on phone or Mac, so I'm going to have to dig it out from Messages.
I thought this was going to be a few minutes' job. I started by scrolling back in Messages, but then realised it would be quicker to find their storage location &amp; sort by date… neither was successful.
If I scroll back a Messages conversation, then for the past six months or so I can see all attachments, pictures etc in-line as normal.
Once I get past that then they've apparently been archived somewhere &amp; I can't find where. I have never 'cleaned' this conversation manually. This appears to be some automatic action taken without my knowledge. I could imagine my phone would do that to save space, but I didn't expect it on the Mac.

If I click on any of those down arrows, the picture will reload. This, as you can imagine, is not the fastest way to find a specific photo :\
If I search in Finder, Kind: jpeg image inside the Attachments folder at ~/Library/Containers/com.apple.iChat/Data/Library/Messages/Attachments I see only the same images as are already inlined. After I refetch an older one, it then appears at today's date.
 Click for full size
Searching the entire drive from Finder gives no other clues.
Using EasyFind to search hidden locations &amp; packages etc for img_ reveals nothing more. BTW, I am not searching for _DSD files, they're from my &quot;proper&quot; photos.
My Messages are synced over iCloud between Mac &amp; iPhone, though very little else is. I don't have my Photos on there, for instance. The only app I sync on iCloud Drive is Maps, nothing else. I sync things like Contacts, Calendars etc, not &quot;multimedia&quot; of any sort, so I don't expect the repository to be iCloud.

Are these images really held in iCloud, even though I haven't asked for them to be?
I am in no way short of data space, 1TB SSD boot drive, only half full &amp; 12TB of other drives in this Mac.  I have none of the iCloud Storage Management options enabled.
macOS 10.14.6 (latest this Mac can run) on Mac Pro 5,1.
After comments
It does appear that these are shuffled off to iCloud, whether you want them to be or not.
From the Details button, top right, then scroll right down - rather blurred picture to demonstrate

Clicking that Download restores them to their correct location. How long before it decides to remove them again I've yet to discover.