I have added webp as a default mapping in the mean time in Runwar.

It does not appear Undertow has a default MIME type for webp files. I entered this ticket for them to add it:

https://issues.redhat.com/browse/UNDERTOW-2218

In the mean time, you can set the MIME type with

• A web.xml override for the stable version of CommandBox

• A new server.json setting in the bleeding edge version of CommandBox

https://ortussolutions.atlassian.net/browse/COMMANDBOX-1345

Ok, that’s more helpful. So it’s the content type that’s wrong. We use Undertow’s default MIME list (though we have the ability to add our own) so I’m surprised Undertow’s core doesn’t have this one already. I’ll check to see if something is configured wrong with Undertow, and if not I’ll add in our own MIME override for it.

The issue is that it doesn’t behave like an image, but a binary. So you can embed it via an img tag, but if you try to view it, it downloads instead of rendering. We just need to add the image/webp mime type to the default list.