Wiki images are supposed to, when it makes sense, have a transparent background so they can work on multiple styles (I know this is not implemented on the wiki yet, but still). I've made the wiki's background slightly transparent so we can tell which images need to be updated. If you see a wiki image with the solid dark blue background, please change it to transparent or link it here and I'll do it.
Edit: Please note that tables are not transparent and this is intentional.
Edit: Please note that tables are not transparent and this is intentional.