I wouldn't be a slideshow per se, but you could do an Item List for your gallery images and order by _item_id DESC - that would show the latest images.
This really should NOT be needed - the default ordering is by primary key (the note_id) - this fix will ensure that it is ordered that way, but I'm not sure why you would have seen this in the first place - I have never seen this on any site.
Sorry for not jumping in here earlier - just an FYI that Proxima 2.0 is just about ready and addresses a lot of issues and adds some cool new features - one of them being a "Single Sign On" option that will allow your apps to "share" user accounts with your JR site, which I think is what will work here.
Something else must be going on here, since there's no way 100 user accounts should get anywhere near 256mb of RAM usage. My guess is that the export is getting stuck in a loop in some place - I will check out the code and see if we are doing any looping in there that might cause this.