ValueError Image has wrong mode when accessing renditions of this particular image.

[salty-ivy]

Description

On a successful upload of this image, it bypasses the image rendition generation.

and on web when trying to access this via CMS admin we get a ValueError and image has wrong mode down from willow/pillow as wagtail tries to regenerate the renditions if not found.

after deleting the wagtail.images.Image instance and corresponding renditions it seems to work.

the Image

Ideas and thoughts

Whole page /admin/images/ becomes inaccessible which is a big issues cause there's no warning at the time of upload.

May be wagtail/willow should throw some error/warning or reject the upload if renditions don't get generated on upload?