When exporting to HTML, image paths in sub-pages are broken, although the images are exported

When exporting to HTML, image paths in sub-pages are broken. The image that it should point to is exported, but the path (img/@src) is broken.

Example:

Broken link:
<img src="download/attachments/27099759/1081791991" ... />

The image that should be referred, is exported, with a path like attachments/27099759/22085636.jpg

The typical symptom of an incorrect path is the following:

• An extra "download" is prepended to the path
• The file ending is always missing.
• Remove the "download" and you have the correct folder, but the image name is wrong