I'm not necessarily sure what they're called, so in lieu of a proper name I'll just call them the bottom-of-page windows. The windows that can be found below an article that link to a variety of wikis with the article name, wiki name and an image from the article. You must know what I mean from that. (I'm a moron, it's just fan feed, please disregard my failings to locate a strip of text properly).
So some of the articles from a wiki I work on come up quite a bit in the bottom-of-page window. Issue is some of the images used in the windows are less than ideal. The images work fine and make sense when you have the caption and a block of text next to it, but when it's just the image and a name they aren't the best choice of image in the article for that character in the vacuum that is the bottom-of-page window. I'm not sure what determines which image is selected (some windows use the second image, some use the twentieth) and whether or not an article will show up in the windows only if it has an image that whatever system deems good for the window.
My question is is there a way to manually select an image an article should use for the window and what actually determines which articles show up there at all. Sorry is this has been answered before but I failed to find it quickly, so here I am.