Image with name starting with "attach:" is broken in view mode when inserted in a page

Steps to reproduce:

• in edit mode, add an image to a page with /image
• upload an image for which name is starting with "attach:"
• the image is displayed in edit mode
• save and quit the edit mode

Expected result: the image is displayed in view mode.

Actual result: the image display is broken in view mode.

Side note: can't upload a test image as Jira is preventing upload of files with ":" in the name.