Board Thread:Support Requests - Getting Started/@comment-46609974-20201007073949/@comment-9605025-20201010184426

The in-infobox-editor button to upload a new image is not available on UCP wikis. For UCP wikis, you need to upload the images prior to editing the infobox. You can do so either using Special:Upload or by using either the single or multiple upload functions of the general (before you start editing the infobox) editor. You will need to know the name of the image you want to add and type in the name. If you want to add multiple images, you need to know each of the names and type something like this. Obviously replacing the image names, image extension, and tab name with whatever is relevant to your situation.