What image formats does BACKGROUNDIMAGE support

Tried with a WebP, but does not work.
Documentation just says images.
Can you list the accepted extensions please.

WebP works fine here.

IMAGE 4.zip (24.6 KB)
using this image, could you check it please.
UPDATE: tried with other WebP and they are not working either.

UPDATE:
using this command
Set BACKGROUNDIMAGE filedisplay:"C:\New Folder\IMAGE 4.webp" BACKGROUNDIMAGEOPTS=aspectfill,shared,opacity:35

Works fine here.

Can you view the image at all in Opus?

Have you turned off the WebP viewer plugin?

Webp's showing fine in viewer.
UPDATE (back at the console):
image
strange though that it is showing in viewer, I think it was turned off to force the Edge one on.

Opus can't load background images via Edge. You'll need to enable the WebP plugin to use them as backgrounds. (Or just use another image format. There's no advantage in using WebP here.)