Nuxeo Studio should place "img" folder in the correct location.

Image resources are being placed in a folder named img at the root of the jar file generated for a Studio project, instead of inside the web/nuxeo.war/img folder.

See for example: https://nos-dev-connect.nos.nuxeo.com/nuxeo/site/studio/ide?project=knowledge-management

Image resources should be placed at web/nuxeo.war/img, or I guess the deployment fragment needs to be updated?