There's actually two culprits here. The first is that we're restricting the pageimages API (which hovercards uses) to only free images. We will be changing this to allow for non-free images from hovercards to appear as well. If you're interested in details, follow this task, which will allow extensions to select whether they want to display any images or free images only. I'd like to note however, that we will only allow for non-free images for the communities which have approved non-free images for a particular extension. The second is that we're pulling images from the entire page, meaning that images which appear later in each article are showing as the images on a hovercard. To account for this, we're restricting the pageimages API to only pull images from the lead section and infobox for an article. For more info on this, check out this task. The results of this for hovercards will be: if the first image in an article is within the infobox or lead section of the article, we will display the image for the hovercard of the article. If an image appears in later sections, no image will be displayed for that article.