UV version:

 universalviewer@4

I'm submitting a:

• bug report => please fork one of these codesandbox examples with a repro of your issue and include a link to it below
• feature request => please use the user stories repo
• support request => Please do not submit support requests here, use stackoverflow

Current behavior:
While reviewing the IIIF cookbook, Simplest Manifest - Single Image File and Image and Canvas with Differing Dimensions were found to be supported in v3 but not v4. In v4, the viewer appears to be using the default extension instead of OSD, and therefore only provides a download option rather than displaying the image.

Expected behavior:
The viewer should display the image, like in v3.

Steps to reproduce:
View in v3 and then try the same manifest in v4 and above.

Other information:
Changing "format": "image/png", to "format": "image/jpeg" is a quick workaround, as seen here, but it would be better to get it back to working how it is.