We'd have to look into that.
On Facebook, it depends on whether Fb has "scraped" the URL yet. If not, you can scrape it yourself via this link:
https://developers.facebook.com/tools/debug/Paste the URL you want to share into the box on that page and click "debug". If you see a message telling you "this URL hasn't been shared on Facebook before", click "Fetch new information".
On the following page, you will likely still not see a preview thumbnail. To make sure Facebook got the right image, wait a few seconds and then click "Scrape again". The preview should then appear. If you then share the link on Facebook, a preview image will be included.
But that's Facebook. I did a quick check for Twitter, but didn't find any such tool immediately. Will have to look into it in more detail.
Ideology: The mistaken belief that your beliefs are neither beliefs nor mistaken.