Forum:How are thumbnail images representing pages selcted?

UPDATE Ah, I found an older discussion of my question here:

http://community.wikia.com/wiki/Forum:Defining_the_image_for_%22Read_more%22_section

So, thanks. Sorry I didn't spot it earlier. G33Z3R 18:11, July 31, 2011 (UTC)

Suppose I have twenty pages on my wiki in the category "Characters". If I go to one of the pages in that category, at the bottom, Wikia (by default) inserts a "Read More" section with three links to other (randomly selected?) pages in that same category. Each of those three links is accompanied by a 200px thumbnail of a picture from the page it links to; or, rarely, an image quoting the first few words of text from that page.

Likewise, if I go to the page "Category:Characters", Wikia automagically created that page, populated with: first eight links in the form of 130px thumbnail images from selected pages in that category, followed by a complete alphabetical listing of the pages in that category (there's a WikiLabs "Category Exposition" tool that Admins can activate to change that display, but the same thumbnails get used, just more of them.) I think the image selected to represent the page here is the same as the image selected to represent the page in my first example, except it's only 130px and cropped differently. (I'm going to guess that some sort of bot works in the background or overnight selecting / preparing these thumbnail images, so changes don't appear immediately.)

Question: How is that image representing the page selected? Often (mostly), it's the image that appears closest to the top of the page, but in some cases the image chosen seems random from elsewhere on the page (and sometimes not particularly representative of the pages content.) Is there any way to specifically designate which image "best represents" a page? Or, at least influence the automatic selection?

Question 1.1: Sometimes, a text sample appears instead of one of the images from the page. Is there any particular reason why a particular page might not be considered to have an appropriate image on it?

I'm happy to read any help pages, but I can't find a hook for where to start. Thanks, G33Z3R 17:25, July 31, 2011 (UTC)