hi! so at w:c:mlp and some other wikis, when you hover over a link to a page on that wiki, the image from the infobox pops up. what do I need to put in common.js for this to happen for my wiki, w:c:nailedit
The MLP wiki uses a custom JS script. I am not sure about the "other wikis" since you haven't mentioned them by name. I know a more common script is LinkPreview. However, I believe this script includes part of the article text. I am not sure if there is a setting to show just the image.
Also, when did you have your wiki's domain changed? It seems the new domain has not yet been registered with InterwikiDispatcher.