I use pearltrees.com to organise bookmarks and resources for my teaching. When a bookmark is added pearltrees will generate a thumbnail for the link. Intrestingly when I added a permalink to a tiddler today the thumbnail on pearltrees is of the tiddler as it was a coupleof days ago, not as the tiddler is now. How???
As it was two days ago, and showing in the thumb nail
As it is right now!
You’d have to look at how Pearltrees generates thumbnails. They may snapshot themselves and only update every so often, they might lean on Wayback Machine etc etc
That’s a good thought. I have no idea. 
It just struck me as odd as it’s not something I’d noticed before!
Interesting!
I assume the Wiki the tiddlers are on is a single file and you are not also using static html tiddlers?
Wherever it sources the content if only a tiddler is retrieved, it may be quite “expensive” as the whole wiki needs to be loaded for the one tiddler , multiple times.
Let us know if you learn any more.
