How to reproduce

• In admin select the "Daily summary mail" of workspaces task and click on "Execute now"
• The user which execute the task is "system user"
• In received mail the avatar is not displayed for users which have a image illustration in their content

org.apache.excalibur.source.impl.SourceResolverImpl#resolveURI:208
at org.apache.excalibur.source.impl.SourceResolverImpl#resolveURI:152
at org.ametys.plugins.core.ui.user.ProfileImageResolverHelper#resolveAsBase64:163

Caused by: org.ametys.runtime.authentication.AccessDeniedException: The user UserIdentity [login=system-user, population=admin_population] cannot be authenticated to the contexts '/sites/intranet', '/sites/demos', '/sites/projet-d-exemple-prive', '/sites/projet1', '/sites/catalog', '/sites/www', '/sites/sitemag', '/sites/event', '/sites/projet-d-exemple-public', '/sites/projet-prive-sur-invitation' because its populations are not part of the 2 granted populations.

Explanation:
We try to resolve the non-authenticated URI "cocoon://_plugins/user-directory/user/ametys_demo_users/admin/image_40?lang=fr"
But this URI does a redirect to "[SITENAME]/_object/catalog/_object/ametys%3Aplugins/contentio/ametys%3Acontents/administrator-user/_attribute/illustration/image/28a_crop42x42.jpg" which is authenticated.
System User has no access to this URI so the resolution failed, unable to get the input stream of image