Board Thread:Support Requests - Designing Your Wiki/@comment-46344595-20201011032632/@comment-9605025-20201011070351

Lifevault, that syntax is for regular images in page content, not images in portable infoboxes. The two are handled differently. Infoboxes only accept the image name or, in the case of tabbed images, gallery tags.

The reason the image isn't automatically expanded to fill the whole width of the infobox is that the wiki doesn't want to expand images beyond their original size. Doing that can cause images to "loose quality". However, if you really want to do this, you can force the image to expand using site CSS.

The wiki already has this in its CSS. Just change it to this instead. You also might want to add the semi-colon after the height like I did in the example. It isn't required but it is good form.