Regarding Facebook forums' hotlinking of external websites' images so that the ones that Facebook selects will appear in Facebook posts that link to such sites: How does one select the image that appears in Facebook's forums whenever one's website's referred to by other publishers within those forums? Here's an example:

Anyhow I uploaded the following html coding (albeit a personally tailored version) to my site, but doing that didn't change the image to which Facebook hotlinks for appearance in its own forums:

<img alt="choose text" src="image.gif">

Perhaps I did something incorrectly? Or maybe Facebook does a memory cache and only refreshes it every few weeks or so? Your feedback would be appreciated, please.