Steps to reproduce:

• Run CQ in standalone mode (disable Confluence Spaces plugin)
• Go to Global Permissions (the CQ version)
• Enable anonymous access to Confluence Questions
• Go to a question with an image attached or directly to the confluence attachment link.

Expected Behaviour

• The Confluence Questions image is displayed

Actual Behaviour
Direct Link:

• The user is redirected to a login prompt
  Confluence Question Page:
• The user is displayed a broken image

Cause?
This seems to happen because Confluence is still respecting the non-CQ, global anonymous usage permissions when accessing attachments/images in Confluence.

Side Note:
If you enable the Confluence Spaces plugin, go to global permissions and enable Use Confluence permissions for anonymous users, then it works as expected once the Confluence Spaces plugin is disabled again. If you leave spaces enabled access issues to images are still prevalent.